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With rapid development of marine infrastructures, materials with better biocorrosion resistance and antibiofouling performance will be highly demanded. Ti6Al4V alloy is susceptible to the above. The inhibition to the microbiologically influenced corrosion of Ti6Al4V-5Cu alloy against Pseudomonas aeruginosa was investigated using antibacterial test, electrochemical techniques, surface analysis, and weight loss test conducted for 2.5 months. At a sputtering depth of 0 nm, the passive film of Ti6Al4V-5Cu alloy was mainly composed of ideal oxide TiO2. With increasing sputtering thickness to 6 nm, Ti2O3 and TiO were detected with a relative fraction of 14.6% and 14.8%, respectively, in the oxide layer of Ti6Al4V-5Cu alloy. In contrast, the outermost layer of Ti6Al4V alloy was predominantly composed of TiO2 but Ti2O3 (22.8%), Al2O3 and V2O5 were also detected. With increasing sputtering depth to 6 nm, fitting revealed the presence of Ti2O3 and TiO with relative fractions of 25.3% and 35.8%, respectively. Yet, a spot of TiO (8%) was also observed at 12 nm in the oxide layer of Ti6Al4V alloy. Although the addition of Cu into Ti6Al4V alloy generated the self-healing property of passive film in the presence of P. aeruginosa, it also reduced resistance to corrosion in general condition.

Control of the formation and stability of reverted austenite is critical in achieving a favorable combination of strength, ductility, and toughness in high-strength steels. In this work, the effects of Cu precipitation on the austenite reversion and mechanical properties of maraging stainless steels were investigated by atom probe tomography, transmission electron microscopy, and mechanical tests. Our results indicate that Cu accelerates the austenite reversion kinetics in two manners: first, Cu, as an austenite stabilizer, increases the equilibrium austenite fraction and hence enhances the chemical driving force for the austenite formation, and second, Cu-rich nanoprecipitates promote the austenite reversion by serving as heterogeneous nucleation sites and providing Ni-enriched chemical conditions through interfacial segregation. In addition, the Cu precipitation hardening compensates the strength drop induced by the formation of soft reverted austenite. During tensile deformation, the metastable reverted austenite transforms to martensite, which substantially improves the ductility and toughness through a transformation-induced plasticity (TRIP) effect. The Cu-added maraging stainless steel exhibits a superior combination of a yield strength of ∼1.3 GPa, an elongation of ∼15%, and an impact toughness of ∼58 J.

A special structure named tetrahedral twin was found in a cold-drawn CoCrFeNi high-entropy alloy. Crystallographic characterization using convergent beam electron diffraction indicated that the three-dimensional (3D) tetrahedral twins were achieved through the intersection of each couple of twin layers in four {111}FCC planes, which was caused by the low stacking fault energy and the special plane strain state during deformation. The calculation results revealed that the tetrahedron-morphological twins could result in significant stress concentration, thereby considerably deteriorating the plasticity of the high-entropy alloy.

To reduce the risk of implant-associated infections, we previously designed and developed a series of medical copper (Cu)-bearing titanium alloys that release Cu ions and hence play an antibacterial role. However, both excessive and deficient Cu levels adversely affect human health; therefore, the aim of the present study was to comprehensively evaluate the short- and long-term biosafety of Cu-bearing titanium alloys (Ti6Al4V-Cu and Ti-Cu) both in vitro and in vivo. Moreover, the predominant kinetic mechanism of Cu ions release and its effect on biosafety were also investigated. The results indicate that the biocompatibility of the Cu-bearing titanium alloys meets the requirements of ISO standards and the Cu ion release kinetics display a good correlation over the entire time period in the normal zero-order model with an almost constant release rate. The release rate maintained at a parts per billion level safe for humans; consequently, we can conclude that our Cu-bearing titanium alloys have satisfactory biocompatibility.

The development of high-efficiency photocatalysts is the primary goal in the field of photocatalytic antibacterial research. In this work, the GaN:ZnO solid solution nanoparticles (NPs) photocatalyst with strong visible absorption and large specific surface area was synthesized via the sol-gel and nitridation reaction process. Also, we systematically investigated the removal efficiency of the organic pollutant and antibacterial activity on E. coli and S. aureus. Notably, methylene blue solution could be completely degraded after 100 min of visible light illumination using 2 mg/mL GaN:ZnO catalyst. Moreover, ~94% of the E. coli were inactivated within 120 min, whereas 100% antibacterial activity against S. aureus was achieved after 90 min of visible light illumination mediated by GaN:ZnO NPs. We further explore the potential mechanism of visible light photocatalytic antibacterial activity enhanced by GaN:ZnO NPs photocatalyst. The current work not only provides a new and efficient photocatalytic antibacterial nanomaterial but also demonstrates its promising applications in environmental and biological fields.

9Cr3W3CoB steels are developed to serve at the temperature range of 620–650 °C, and have been recognized as the most promising martensitic heat-resistant steels for supercritical power plants. Due to the high W and Co contents, the Fe2W Laves phase in such 9Cr3 W3CoB steel possesses some specialties in thermodynamics. In the present research, it was found that even when aged at 800 °C in the 9Cr3W3CoB steel, instead of dissolving, Laves phase formed after 50 h and kept on increasing in size and number density until 1000 h, indicating that the Laves phase was marching for the thermodynamic equilibrium during aging. In this thermodynamic process, the W-rich M3B2 borides in as-received steel and M23C6 carbides were revealed to dissolve, supporting the growth of Laves phase. SEM investigation indicates that Laves phase tended to form clusters, and finally grow as a unit bulk Laves phase with an irregular shape. Besides, Laves phase nucleated next to M23C6 carbides and enwrapped them inside at 800 °C. In addition, the growth processes of Laves phase and M23C6 carbides were a competitive procedure, the coarsening of M23C6 carbides was prior to the growth of Laves phase at 750 °C while the growth of Laves phase was prior to the coarsening of M23C6 carbides at 800 °C.

Mg–Zn–Nd alloy is a promising biodegradable metal material for surgical staples during the reconstruction of digestive tract due to its good biocompatibility and suitable mechanical properties. However, its deformation property and corrosion resistance should be improved to make better safety and effectiveness of staples. In the present study, bi-direction drawing was adopted to maintain the initial texture characteristics, and improve mechanical property and corrosion resistance of Mg–2Zn–0.5Nd alloy. The results showed that the microstructure after bi-direction did not change too much, but the texture could maintain its initial characteristics. The ductility of the alloy with 60 % accumulative area reduction after bi-direction drawing was increased by 70 %, indicating that an outstanding deformation property of Mg–Zn–Nd alloy can be obtained by bi-direction drawing. The corrosion resistance was also improved after bi-direction drawing compared with that under single direction drawing.

The adsorption behavior, antibacterial, and corrosion properties of a Ti-3Cu alloy were studied in a phosphate-buffered saline solution containing 0, 1, 3, and 6 g L−1 bovine serum albumin protein at 37 °C and pH = 7.4 (±0.2). The protein adsorption behavior was examined via cyclic voltammetry, secondary ions mass spectroscopy (SIMS), and angle-resolved X-ray photoelectron spectroscopy (ARXPS). The corrosion property was analyzed by the open circuit potential (OCP), potentiodynamic polarization (PD), and electrochemical impedance spectroscopy (EIS) examinations. The antibacterial test was conducted according to the GB/T 21510 China Standard. It was observed that the surface charge density (QADS) was directly proportional to the amount of the adsorbed BSA protein, signifying that the protein adsorption was accompanied by the charge transfer, pointing to chemisorptions phenomena. BSA amino groups and other organic species were observed in the surface analysis examinations. It was shown that the formation of barrier complexes between the TiO2 oxide-layer and PBS solution resulted in decreasing the release of Cu-ions, which consequently reduced the antibacterial activity. On the other hand, these barrier complexes improved the corrosion resistance by increasing the charge transfer resistance and double-layer capacitance of the Ti-3Cu alloy.

Osteoporotic fracture with increase of aging population became an urgent orthopedic problem. Bisphosphonates were widely recommended as effective clinical treatment drugs. Combination of biodegradable Mg-based implants and merits of bisphosphonates was suggested for osteoporotic fracture healing. Considering the mild and sustained drug release, a novel one-step electrodeposition synthesis of drug loaded coating was proposed in this study. In comparison to conventional soaking method, encapsulated zoledronate coating by one-step electrodeposition method could modulate drug release in first diffusion-controlled and later degradation-controlled manner. The in vitro cell response to zoledronate loaded coating showed enhanced proliferation and osteogenic differentiation of osteoblasts and no significant inhibition on osteoclasts, which could improve bone-forming and decrease bone resorption due to osteoporosis.

Nowadays, the employing of molecular imprinting technique in the analysis and separation of proteins from complex biological samples has been widely favored by researchers. To enrich the types of surface protein imprinted materials and expand the application fields of graphene materials, novel surface molecular imprinted polymers (MIPs) based on magnetic graphene microspheres Fe3O4@rGO@MIPs are first synthesized in this paper. Fe3O4@rGO@MIPs are prepared by oxidative self-polymerization of dopamine on the surface of magnetic graphene (Fe3O4@rGO) composite microspheres. Bovine serum albumin (BSA) is selected as protein template. Fe3O4@rGO microspheres with wrinkled flower-like structure are obtained by compounding Fe3O4 and graphene oxide in an appropriate ratio via the method of high-temperature reduction self-assembly. The microspheres exhibit promising dispersibility, high external surface area, rich pore structure, and sufficient magnetic properties. These advantages not only prevent the agglomeration of imprinted microspheres in the aqueous phase, which is conducive to contact and static adsorption, but also increase the amount of protein imprinting. Additionally, sufficient magnetic properties ensure fast and effective separation of the adsorbents. While the adsorption capacity is increased, the separation procedure becomes simple. The binding capacity of Fe3O4@rGO@MIPs for BSA can reach 317.58 mg/g within 60 min, and the imprinting factor (IF) is 4.24. More importantly, Fe3O4@rGO@MIPs can specifically recognize the target BSA from the mixed proteins and the actual sample. There is no significant decrease in the adsorption amount, IF, and magnetic properties after eight runs. It is promising to be used in the separation of proteins from the actual biological samples.

Frequent food poisoning and food-borne diseases outbreaking in recent years have caused people to attach great attention to food safety, especially the food contact materials that are essential in the food industrial chains and daily lives, ensuring their clean sanitation are of great importance in blocking microbial contamination and spread of food-borne pathogens. Stainless steel (SS) is one of the most accepted and widely used food contact material, and the Cu-bearing SS possesses excellent antibacterial performance and maintains the original mechanical properties of SS, maybe making it a better substitute for the conventional SS in the food area. Taking advantages of bactericidal and antifouling properties of Cu-bearing SS, this study simulated a variety of food contact scenarios, explored a new strategy for food preservation and food safety by using Cu-bearing SS as a food contact material. The results showed that the Cu-bearing SS could not only delay the spoilage of different foods by inhibiting the activity of microorganisms in foods, but also reduce the expressions of spoilage traits of bacteria as well as the formation of biofilms by quenching the quorum-sensing signals, and further creating a good bacteriostatic atmosphere for the contacted food and its surrounding environment. In addition, the remarkable antifouling property of Cu-bearing SS would give the material a self-cleaning feature for food applications, which can avoid secondary contamination of food as a source of contamination. This study well demonstrates that the Cu-bearing SS has broad application potentials and prospects in the food area.

304 stainless steel (SS) used as orthodontic wire during orthodontics faces the risk of microbiologically influenced corrosion (MIC) due to diverse flora environment. Hereinto, Streptococcus mutans (S. mutans) is the most important cariogenic bacteria. In this work, MIC behavior of a new 304-Cu SS in presence of S. mutans was studied by the observations using scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) including live/dead staining, extracellular polymeric substance (EPS) staining and pitting corrosion, electrochemical test, and X-ray photoelectron spectroscopy (XPS). Above results showed that 304-Cu SS possessed excellent biofilm inhibition ability and presented lower corrosion current density (icorr), larger polarization resistance (Rp) and charge transfer resistance (Rct) in the presence of S. mutans, indicating that 304-Cu SS had a better MIC resistance against S. mutans. It was further affirmed by XPS results that the presence of Cu-oxide in passive film of 304-Cu SS inhibited the formation of biofilm.

Stainless steel (SS) has unsatisfied corrosion resistance in many aggressive environments, particularly under a low pH condition in the bioleaching industry. In this study, through surface analyses and electrochemical measurements, the corrosion resistance of a novel Cu-bearing 316 L SS was evaluated in the presence of an acid-producing bacterium, Acidithiobacillus caldus SM-1 that was able to create an extremely acidic corrosive environment. The significantly enhanced anti-microbiologically-induced-corrosion performance could be explained by the intracellular reactive oxygen species (ROS) and Fenton reaction on the Cu-bearing 316 L SS.

The oxidation behavior of two Ferritic/Martensitic (F/M) steels including novel SIMP steel and commercial P91 steel were investigated by exposure to flowing deaerated supercritical water (SCW) at 700 °C for up to 1000 h. The kinetic weight gain curves follow parabolic and near-cubic rate equations for SIMP and P91 steels, respectively. X-Ray Diffraction analysis showed the presence of magnetite and a spinel phase in flowing SCW for both steels. The morphology and structure of the oxide scales formed on these two steels were analyzed. The relationship between the microstructure and oxidation behavior and the reason that SIMP steel showed better oxidation resistance than P91 steel were discussed.

Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) are the most typical pathogenic bacteria with a significantly high risk of bio-contamination, widely existing in hospital and public places. Recent studies on antibacterial materials and the related mechanisms have attracted more interests of researchers. However, the antibacterial behavior of materials is usually evaluated separately on the single bacterial strain, which is far from the practical condition. Actually, the interaction between the polymicrobial communities can promote the growing profile of bacteria, which may weaken the antibacterial effect of materials. In this work, a 420 copper-bearing martensitic stainless steel (420CuSS) was studied with respect to its antibacterial activity and the underlying mechanism in a co-culturing infection model using both E. coli and S. aureus. Observed via plating and counting colony forming units (CFU), Cu releasing, and material characterization, 420CuSS was proved to present excellent antibacterial performance against the mixed bacteria with an approximately 99.4 % of antibacterial rate. In addition, 420CuSS could effectively inhibit the biofilm formation on its surfaces, resulting from a synergistic antibacterial effect of Cu ions, Fe ions, reactive oxygen species (ROS), and proton consumption of bacteria.

Torsional properties are important performance parameters for bone screw applications, but they are seldom studied, especially for newly developed biodegradable Mg alloys. In this study, WE43 Mg alloy with different microstructures was achieved by equal channel angular pressing (ECAP) and heat treatment, and their torsional properties were studied. In addition, tensile properties were also tested as a comparison. The results indicated that grain refinement led to higher torsional strength and ductility, while the second phases improved the torsional strength but reduced the ductility. The texture was strengthened after ECAP, as a result the tensile strength increased, but the torsional strength did not increase and even decreased, especially for 2-pass ECAP sample with a typical basal fiber texture. The basal plane orientation deviation from the extrusion direction after 4-pass ECAP resulted in higher torsional strength and lower torsional ductility, but lower tensile strength and higher tensile ductility were obtained. This implied that a strong fiber texture would reduce the torsional strength but improve the torsional ductility, which was different from its effect on tensile properties.

Ti-15Zr-xCu (3 ≤ x ≤ 7, wt.%) novel antibacterial and antibiofilm alloys with competitive mechanical properties, biological responses and corrosion resistance were designed and fabricated. Annealing heat treatment on Ti-15Zr-7Cu (TZC-7A), after holding for 2 h at slightly above their beta transus temperature (BTT) ensured their tensile strength (UTS), yield strength (YS) and hardness (HRV) were improved by 31.2%, 20% and 12.3% respectively compared to the control without Cu, Ti-15Zr (T-15ZA). Although the 3 wt.% Cu alloy displayed the highest elongation (26%), the TZC-7A alloy also possessed a good ductility. Presence of evenly dispersed Ti2Cu and Zr2Cu Cu-rich intermetallic phases formed as interwoven and alternating lamellae within the α + β matrix as a result of Cu addition, as revealed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). These greatly contributed to their strengthening and bactericidal properties. Over 98% antibacterial effect against E. coli and S. aureus have been imparted, coupled with excellent biofilm inhibition. Potentiodynamic polarization curves showed that the TZC-7A alloy possessed higher corrosion resistance than commercially pure titanium, cp-Ti; contact angle test revealed enhanced hydrophilicity; while confocal laser scanning microscopy (CLSM) and cell counting kit (CCK-8) assays also displayed drastically lowered bacterial adhesion rate with comparatively no cytotoxicity. Cell attachment on all alloys was similar but the best spread was obtained on TZC-7A after 24 h. The developed alloy has good potential as an antibacterial implant material with combination of optimized properties.

Cu has been proved to possess various beneficial biological activities, while sandblasting and acid etching (SLA) is widely used to modify the commercial dental implant in order to improve osseointegration. Based on the above, a novel antimicrobial dental implant material, Ti-Cu alloy, was treated with SLA, to combine chemical design (Cu addition) and topographical modification (SLA). In this work, the effects of SLA treated Ti-Cu alloys (Ti-Cu/SLA) on osteogenesis, angiogenesis and antibacterial properties were evaluated from both in vitro and in vivo tests, and Ti/SLA and Ti-Cu (without SLA) were served as control groups. Benefiting by the combined effects of chemical design (Cu addition) and micro-submicron hybrid structures (SLA), Ti-Cu/SLA had significantly improved inhibitory effects on oral anaerobic bacteria (P. gingivalis and S. mutans) and could induce upregulation of osteogenic-related and angiogenic-related genes expression in vitro. More importantly, in vivo studies also demonstrated that Ti-Cu/SLA implants had wonderful biological performance. In the osseointegration model, Ti-Cu/SLA implant promoted osseointegration via increasing peri-implant bone formation and presenting good bone-binding, compared to Ti/SLA and Ti-Cu implants. Additionally, in the peri-implantitis model, Ti-Cu/SLA effectively resisted the bone resorption resulted from bacterial infection and meanwhile promoted osseointegration. All these results suggest that the novel multiple functional Ti-Cu/SLA implant with rapid osseointegration and bone resorption inhibition abilities has the potential application in the future dental implantation.

A TiN interlayer with high electrical conductivity was prepared between the GH3535 alloy and the Ni coating as a diffusion barrier to elements interdiffusion with the goal of increasing the corrosion resistance of GH3535 alloy in molten FLiNaK salt at 700 ℃. Results indicated that Ni coating could be directly electroplated on the TiN coated GH3535 alloy without extra conductive transition layer. TiN layer showed excellent thermal and chemical stabilities at elevated temperature in this molten salt system, without phase decomposition. The Ni/TiN composite coating was stable enough to resist corrosion in LiF-NaF-KF molten salt at 700 ℃. Elements interdiffusion between the substrate and Ni coating could be effectively inhibited and the corrosion resistance of the alloy was greatly enhanced. Besides, the TiN interlayer remained continuous and well adhered to the Ni coating as well as the substrate after corrosion test.

In this study, the CoCrW-xCu alloys (x = 2, 3 and 4 wt%) were fabricated using selective laser melting (abbreviated as Co-2Cu, Co-3Cu and Co-4Cu) with the purpose of reducing the inflammation responses and the activity of osteoclast. The metal ions releasing test showed that when the Cu content was less than 4 wt%, the releasing amount of Co and Cr ions was very small; however, when 4 wt% Cu was added in the CoCrW based alloy, the quantity of Co ions was significantly elevated with respect to the other groups due to the segregation of precipitates in the matrix; the Cu2+ ion quantity of the Co-2Cu, Co-3Cu and Co-4Cu alloys were 0.05, 0.09 and 0.27 μg/(L cm2) after 7 d immersion, respectively; the RT-qPCR and ELISA data indicated that the expression levels of the pro-inflammatory cytokines (TNF-α and IL-6) were down-regulated in the Co-3Cu and Co-4Cu groups, whereas the expression level of the anti-inflammatory cytokine (IL-10) was up-regulated in all CoCrW-xCu alloys; meanwhile, the Cu-containing CoCrW alloys significantly down-regulated the expression of the NF-κB signal pathway in a Cu content-dependent manner, and the downstream transcription factors of NF-κB signal pathway including NFATc1, TRAP and Cath-K were also down-regulated via potentially manipulating the NF-κB signal pathway. After comprehensive consideration, it is considered that the Co-3Cu alloy is a potential material for self-alleviating inflammatory responses.

Bone plates play a vital role in bone fracture healing by providing the necessary mechanical fixation for fracture fragments through modulating biomechanical microenvironment adjacent to the fracture site. Good treatment effect has been achieved for fixation of bone fracture with conventional bone plates, which are made of stainless steel or titanium alloy. However, several limitations still exist with traditional bone plates including loosening and stress shielding due to significant difference in modulus between metal material and bone tissue that impairs optimal fracture healing. Additionally, due to demographic changes and non-physiological loading, the population suffering from refractory fractures, such as osteoporosis fractures and comminuted fractures, is increasing, which imposes a big challenge to traditional bone plates developed for normal bone fracture repair. Therefore, optimal fracture treatment with adequate fixation implants in terms of materials and design relevant to special conditions is desirable. In this review, the complex physiological process of bone healing is introduced, followed by reviewing the development of implant design and biomaterials for bone plates. Finally, we discuss recent development of hybrid bone plates that contains bioactive elements or factors for fracture healing enhancement as a promising direction. This includes biodegradable Mg-based alloy used for designing bone screw-plates that has been proven to be beneficial for fracture healing, an innovative development that attracts more and more attention. This paper also indicates that the tantalum bone plates with porous structure are also emerging as a new fracture internal fixation implants. The reduction of the stress shielding is verified to be useful to accelerate bone fracture healing. Potential application of biodegradable metals may also avoid a second operation for implant removal. Further developments in biometals and their design for orthopedic bone plates are expected to improve the treatment of bone fracture, especially the refractory fractures.

As a metallic orthopedic implant, 316 L stainless steel (316 L SS) is used extensively for its good resistance to corrosion and mechanical properties. However, it takes a long time to achieve osseointegration between 316 L SS and adjacent tissues due to its bio-inert characteristic. Hence, the aim is to improve the bio-adaption of 316 L SS. A good approach is to add elements to materials to improve their osteogenic capabilities by the appropriate release of ions. Hence copper-containing 316 L stainless steel (316L-Cu SS) was investigated in this work, where Cu is an essential trace element that can stimulates osteogenesis. It was found that 316L-Cu SS was bio-safe and did not affect the proliferation of co-cultured osteoblasts in comparison with 316 L SS. It increased cell apoptosis on day 1 but inhibited it on day 3, which cooperates with new bone formation processes. Osteoblasts extend themselves more quickly and in a better manner on the surface of 316L-Cu SS, wheneven more pseudopodia are present. Furthermore, the gene expression of alkaline phosphatase, collagen I and runt-related transcription factor 2 (Runx2) in osteoblasts cultured with 316L-Cu SS was significantly enhanced. Runx2 protein expression increased, and osteogenesis was stimulated by 316L-Cu SS via an Akt cell signaling pathway. In conclusion, 316L-Cu SS stimulates osteogenesis through activation of the Akt cell signaling pathway and the upregulation of Runx2. Thus, 316L-Cu SS is a promising material that may be used in surgical implants to stimulate osteogenesis.

Acid producing bacterium Acetobacter aceti causes pitting corrosion of stainless steel (SS). This work investigated the enhanced resistance of 2205-Cu duplex stainless steel (DSS) against biocorrosion by A. aceti in comparison with 2205 DSS using electrochemical and surface analysis techniques. With the addition of Cu to 2205 DSS, biofilms on the 2205-Cu DSS surface were inhibited effectively. The largest pit depth on 2205-Cu DSS surface in the presence of A. aceti was 2.6 μm, smaller than 5.5 μm for 2205 DSS surface. The icorr was 0.42 ± 0.03 μA cm−2 for 2205-Cu DSS in the biotic medium, which was much lower than that for 2205 DSS (3.69 ± 0.65 μA cm−2). All the results indicated that the A. aceti biofilm was considerably inhibited by the release of Cu2+ ions from the 2205-Cu DSS matrix, resulting in the mitigation of biocorrosion by A. aceti.

In the present work, the biodegradable behavior, cytocompatibility and osteogenesis activity of a Mg69Zn27Ca4 metal glass were investigated. Electrochemical test, immersion test, cytotoxicity test and histopathological evaluation were carried out. The results showed that there was a dense protective layer formed on the surface of Mg69Zn27Ca4 metal glass which could inhibit the degradation process in the Hank’s solution. In vitro cytotoxicity test showed that Mg69Zn27Ca4 metal glass had good biocompatibility. Histopathological evaluation showed that the degradation of Mg69Zn27Ca4 metal glass could promote the new bone formation with no obvious inflammatory reactions. After 2 months implantation, the diameter of the bone defect was reduced from the original φ6 mm to φ3.35 ± 0.40 mm with the degradation of Mg69Zn27Ca4 metal glass. Therefore, it can be concluded that Mg69Zn27Ca4 glass has great potential to be used as bone substitutes.

The Ti6Al4V-Cu alloy was reported to show good antibacterial properties, which was promising to reduce the hazard of the bacterial infection problem. For the purpose of preparing Ti6Al4V-Cu alloy with satisfied comprehensive properties, it’s important to study the heat treatment and the appropriate Cu content of the alloy. In this study, high Cu content Ti6Al4V-xCu (x = 4.5, 6, 7.5 wt%) alloys were prepared, and firstly the annealing heat treatments were optimized in the α+β+Ti2Cu triple phase region to obtain satisfied tensile mechanical properties. Then the effect of Cu content on the tribological property, corrosion resistance, antibacterial activity and cytotoxicity of the Ti6Al4V-xCu alloys were systematically studied to obtain the appropriate Cu content. The results showed that the optimal annealing temperatures for Ti6Al4V-xCu (x = 4.5, 6, 7.5 wt%) alloys were 720, 740 and 760 °C, respectively, which was resulted from the proper volume fractions of α, β and Ti2Cu phases in the microstructure. The additions of 4.5 wt% and 6 wt% Cu into the medical Ti6Al4V alloy could enhance the wear resistance and corrosion resistance of the alloy, but the addition of 7.5 wt% Cu showed an opposite effect. With the increase of the Cu content, the antibacterial property was enhanced due to the increased volume fraction of Ti2Cu phase in the microstructure, but when the Cu content was increased to 7.5 wt%, cytotoxicity was presented. A medium Cu content of 6 wt%, with annealing temperature of 740 °C make the alloy possesses the best comprehensive properties of tensile properties, wear resistance, corrosion resistance, antibacterial property and biocompatibility, which is promising for future medical applications.

Ti-Cu alloys with different Cu contents (3, 5 and 7 wt%) were fabricated and studied as novel antibacterial biomaterials for dental application. The Ti-Cu alloys were annealing treated at different temperatures (740 °C, 830 °C and 910 °C) in order to obtain three typical microstructures, α-Ti + Ti2Cu, α-Ti + transformed β-Ti, and transformed β-Ti. Mechanical, antibacterial and biocorrosion properties of Ti-Cu alloys with different microstructures were well analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), tensile test, electrochemical test and antibacterial test. The results indicated that the Ti-Cu alloys with microstructure of α-Ti + Ti2Cu showed the best ductility compared with other Ti-Cu alloys with microstructures of α-Ti + transformed β-Ti and complete transformed β-Ti, and meanwhile, increase of the Cu content significantly contributed to the decreased ductility due to the increasing amount of Ti2Cu, which brought both solid solution strengthening and precipitation strengthening. Finally, the Ti-5Cu alloy with microstructure of α-Ti + Ti2Cu exhibited excellent ductility, antibacterial property and corrosion resistance, providing a great potential in clinical application for dental implants.

RE-containing Mg alloys used as biodegradable medical implants exhibit good promising application due to their good mechanical properties and degradation resistance. In this work, effect of Gd on the microstructure, mechanical properties and biodegradation of as-cast Mg-2Zn-xGd-0.5Zr alloys was investigated. The results showed that there were mainly α-Mg, I-phase, W-phase and MgZn2 phase in Mg-Zn-Gd-Zr alloys. With increase of the Gd content, the strength of the alloys was enhanced due to the second phase strengthening and grain refinement. The degradation resistance of Mg-2Zn-0.5Zr alloy was increased by adding 0.5%–1% Gd due to the uniformly distributed second phases which acted as a barrier to prevent the pitting corrosion. However, increasing Gd content to 2% reduced the degradation resistance of the alloy due to the galvanic corrosion between the matrix and the second phases. The good degradation resistance and mechanical properties of as-cast Mg-2Zn-1Gd-0.5Zr alloy makes it outstanding for biomaterial application.

A high Si reduced activation ferritic/martensitic (RAFM) steel for nuclear structure application is successfully designed by using Calphad method. The main designed chemical composition is C 0.18–0.22%, Cr 10.0–10.5%, W 1.0–1.5%, Si 1.0–1.3%, V+Ta 0.30–0.45%, and Fe in balance. High Si design brings excellent corrosion resistance, while low activation is advantageous in the nuclear waste processing. The experimental results indicate that the newly designed high Si RAFM steel had full martensitic structure and uniformly distributed fine second phase particles, and exhibited excellent mechanical properties and corrosion resistance. Compared to the P91 steel, this new RAFM steel designed by Calphad method is expected to be a promising candidate used in nuclear power generation, which also provides a new and effective approach to the development of RAFM steel for nuclear application.

Polymer coating was widely used as a protective coating on Mg alloy stent due to its excellent deformability. However, the polymer coating with lots of macro- and micro-holes after solvent evaporation during forming process would make corrosion medium permeate easier and decrease the corrosion resistance of Mg alloy stent. In this study, a novel critical re-melting method was adopted to improve the polymer coating densification, which was evaluated by the surface morphology of coating. The corrosion resistance of Mg alloy stent after critical re-melting treatment was examined by the electrochemical and immersion tests. The results indicated that the corrosion resistance of Mg alloy stent with polymer coating was improved significantly by polymer critical re-melting treatment.

Microbiologically influenced corrosion (MIC) is a big threat to the strength and safety of many metallic materials used in different environments throughout the world. The metabolites and bioactivity of the microorganisms cause severe deterioration on the metals. In this study, MIC of pure titanium (Ti) was studied in the presence of a highly corrosive aerobic marine bacterium Pseudomonas aeruginosa. The results obtained from electrochemical test showed that Ti was corrosion resistant in the abiotic culture medium after 14 d, while the increased corrosion current density (icorr) obtained from polarization curves and the decreased charge transfer resistance (Rct) from electrochemical impedance spectroscopy (EIS) indicated the accelerated corrosion of Ti caused by P. aeruginosa biofilm. For further confirmation of the above results, the surface of Ti was investigated using scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM) and X-ray photoelectron spectroscopy (XPS). According to the XPS results, TiO2 was formed in both abiotic and biotic conditions, while unstable oxide Ti2O3 was detected in the presence of P. aeruginosa, leading to the defects in the passive film and localized corrosion. Pitting corrosion was investigated with the help of CLSM, and the largest pit depth found on Ti surface immersed in P. aeruginosa was 1.2 μm. Ti was not immune to MIC caused by P. aeruginosa.

Microbiologically influenced corrosion (MIC) is becoming a serious problem for buried pipelines. Developing environmentally friendly strategies for MIC control is increasingly urgent in oil/gas pipeline industry. Copper (Cu) in steels can not only provide aging precipitation strengthening, but also kill bacterium, offering a special biofunction to steels. Based on the chemical composition of traditional X80 pipeline steel, two Cu-bearing pipeline steels (1% Cu and 2% Cu) were fabricated in this study. The microstructure, mechanical properties and antibacterial property against sulphate-reducing bacteria (SRB) and Pseudomonas aeruginosa (P. aeruginosa) were studied. It was found that the novel pipeline steel alloyed by 1%Cu exhibited acicular ferrite microstructure with nano-sized Cu-rich precipitates distribution in the matrix, resulting in better mechanical properties than the traditional X80 steel, and showed good MIC resistance as well. The pitting corrosion resistance of 1% Cu steel in as-aged condition was significantly better than that of X80 steel. A possible antibacterial mechanism of the Cu-bearing pipeline steel was proposed.

The antibacterial Cu-bearing 304L stainless steel is a new kind of structural and functional integrated metal material. In this work, evolution behavior of passive film of different heat treated Cu-bearing 304L stainless steel immersed in 0.5 M H2SO4 solution was investigated by using electrochemical measurements, atomic force microscopy (AFM) observation and X-ray photoelectron spectroscopy (XPS) analysis. The results show that the solution and aging treated samples have the similar polarization behaviors. The passive film impedance experiences an initial decrease within 7 days followed by a subsequent increase, while the defect density of passive film presents the opposite trend. Meanwhile, the evolution of surface morphology and the estimated thickness of the passive film confirm that it experiences initial dissolution and follow-up repair. Furthermore, the Cr3+ content in passive film undergoes sequential reduction to increase, however the variation tendency of Cu2+ content is just opposite, indicating that the content variation of Cr and Cu in passive film reflects the competitive process of film dissolution and repair. In addition, compared with solution treated samples, aged samples have a bigger icorr value and the rougher passive film. This indicates that the passive film of solution treated steel is more compact and stable.

We investigated the deformation behavior of a new biomedical Cu-bearing titanium alloy (Ti-645 (Ti-6.06Al-3.75V-4.85Cu, in wt%)) to optimize its microstructure control and the hot-working process. The results showed that true stress–true strain curve of Ti-645 alloy was susceptible to both deformation temperature and strain rate. The microstructure of Ti-645 alloy was significantly changed from equiaxed grain to acicular one with the deformation temperature while a notable decrease in grain size was recorded as well. Dynamic recovery (DRV) and dynamic recrystallization (DRX) obviously existed during the thermal compression of Ti-645 alloy. The apparent activation energies in (α + β) phase and β single phase regions were calculated to be 495.21 kJ mol−1 and 195.69 kJ mol−1, respectively. The processing map showed that the alloy had a large hot-working region whereas the optimum window occurred in the strain rate range of 0.001–0.1 s−1, and temperature range of 900–960 °C and 1000–1050 °C. The obtained results could provide a technological basis for the design of hot working procedure of Ti-645 alloy to optimize the material design and widen the potential application of Ti-645 alloy in clinic.

The effect of Co addition on the formation of Ni-Ti clusters in maraging stainless steel was studied by three dimensional atom probe (3DAP) and first-principles calculation. The cluster analysis based on the maximum separation approach showed an increase in size but a decrease in density of Ni-Ti clusters with increasing the Co content. The first-principles calculation indicated weaker Co-Ni (Co-Ti) interactions than Co-Ti (Fe-Ti) interactions, which should be the essential reason for the change of distribution characteristics of Ni-Ti clusters in bcc Fe caused by Co addition.

Although already scientists in recent years have reported some experimental and theoretical results of La-Ni-Al series of tritium-storage alloys, several key aspects remain the subject of considerable debate. In an effort to interpret some of these unknowns, we have performed experimental and theoretical investigations for LaNi5-xAlx (x = 0, 0.25, 0.5, 0.75 and 1.0) tritium-storage alloys. Firstly, the XRD characterization indicates that the unit cell volumes of LaNi5-xAlx increase with Al content in alloys. Secondly, the PC-isotherm measurement of LaNi5-xAlx alloys shows that their hydrogen absorption/desorption plateau pressures reduce with the increase of Al content while their plateau widths narrow simultaneously. The deuterium absorption/desorption plateaus have a similar trend to hydrogen’s except for their plateaus being higher than hydrogen’s. To explain the above experimental findings, a series of calculations based on density functional theory (DFT) and frozen phonon approach have been performed. The results manifest that: (1) the partial substitutions of Al for Ni reduce the hydrogen formation energies of LaNi5-xAlxH and the number of available interstitial sites, and therefore lead to the absorption/desorption plateau pressures being reduced and the plateau widths being narrowed down at the same experimental temperatures; (2) the covalent interaction between H and Ni is an important factor for estimating the stability of LaNi5-xAlx-H system; (3) since the calculated enthalpy change ΔH is generally more accurate than the calculated entropy change ΔS with respect to the corresponding experimental value for each LaNi5-xAlx-H (or D), the curves of ΔH vs. hydrogen storage capacity instead of Van’t Hoff relation, can be used to predict the experimental plateau pressures of LaNi5-xAlx-H (D or T) at a given temperature; (4) the hydrogen isotope effect of LaNi5-xAlx-H (D or T) system can be quantitatively described as a linearity relation between ΔZPE + ΔHvib and 1 / m Q (Q = H, D, T). From the good agreement between the predicted and experimental ln ( P H / P 0 ) and ln ( P D / P 0 ) , it is deduced that predicting ln ( P T / P 0 ) of LaNi5-xAlxT is feasible. The procedure of pre-computing and comparing curves of ΔH vs. hydrogen storage capacity proposed in this paper provided an attractive tool to increase the efficiency of experimental alloying design of hydrogen (deuterium or tritium) storage materials.

An antibacterial 2205-Cu duplex stainless steel (DSS) was shown to inhibit the formation and growth of corrosive marine biofilms by direct contact with copper-rich phases and the release of Cu2+ ions from the 2205-Cu DSS surface. In this work, the microbiologically influenced corrosion (MIC) resistance of 2205-Cu DSS in the presence of the corrosive marine bacterium Pseudomonas aeruginosa was investigated. The addition of copper improved the mechanical properties such as the yield strength, the tensile strength and the hardness of 2205 DSS. Electrochemical test results from linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS) and critical pitting temperature (CPT) measurements showed that 2205-Cu DSS possessed a larger polarization resistance (Rp), charge transfer resistance (Rct) and CPT values, indicating the excellent MIC resistance of 2205-Cu DSS against the corrosive P. aeruginosa biofilm. The live/dead staining results and the SEM images of biofilm confirmed the strong antibacterial ability of 2205-Cu DSS. The largest pit depth of 2205-Cu DSS was considerably smaller than that of 2205 DSS after 14 d in the presence of P. aeruginosa (2.2 μm vs 12.5 μm). 2205-Cu DSS possessed a superior MIC resistance to regular 2205 DSS in the presence of aerobic P. aeruginosa.

Natural graphite is investigated as the cathode for aluminum ion batteries in recent years. However, some drawbacks of the natural graphite such as severe volume swelling shorten its lifetime. In this work, we prepared a composite material by depositing an amorphous carbon on the graphite paper. The composite was used as a cathode to study the electrochemical performance in aluminum ion batteries. The charge/discharge results showed that the composite could exhibit a longer cycle life than the graphite paper. Electrochemical analyses demonstrated that the interface between the amorphous carbon and the graphite paper made a major contribution to the improvement of the cycling stability.

Due to the excellent mechanical properties, good corrosion resistance, high biocompatibility and nickel-free character, the high nitrogen nickel-free austenitic stainless steel (HNASS) becomes an ideally alternative material for coronary stents. Stent implantation works in harsh blood environment after a balloon dilatation, i.e., the material is used in a corrosive environment with a permanent deformation. The present study attempts to investigate effects of pre-straining on high-cycle fatigue behavior and corrosion fatigue behavior of HNASS in Hank’s solution and the relevant mechanism for coronary stents application. It is found that higher pre-straining on HNASS results in higher strength and maintains almost same corrosion resistance. Fatigue limit of 0% HNASS is 550 MPa, while corrosion fatigue limit is 475 MPa. And improvement in fatigue limit of 20% and 35% pre-strained HNASS is in comparison with the 0% HNASS, while corrosion would undermine the fatigue behavior of HNASS. In a suitable range, the pre-straining had a beneficial effect on corrosion fatigue strength of HNASS, such as nearly 300 MPa improved with 20% cold deformation. This result provides a good reference for predicting the life of HNASS stent and as well its design.

Al–Ga–Sn, Al–Ga–In and Al–Ga–In–Sn alloys were prepared using arc melting technique. Their microstructures were investigated by X-ray diffraction and scanning electron microscopy with energy dispersed X-ray. Based on microstructure analysis, the phase constituents of alloys at Al grain boundaries were identified. The melting points of Al grain boundary phases were measured using differential scanning calorimeter. The reactivities of Al–water at different water temperatures indicate that liquid Al grain boundary phases promote Al–water reactions of alloys. The melting points of Al grain boundary phases affect the reaction temperatures of Al–water, leading to different reaction temperatures of alloys. The measured H2 generation rate and yields of alloys are related to the compositions of alloys. The theory of micro-galvanic cell is used to explain the observed different H2 generation rates of alloys.

LaNi 3.8 Al 1.0 Mn 0.2 alloy was prepared by vacuum induction melting and melt-spinning. The effects of different preparation techniques of the as-cast, cast then annealed, as-spun and spun then annealed alloys on the microstructure and hydrogen storage properties were investigated. The results indicated that the non-CaCu 5 phases in the alloy became tinier and more dispersive after annealing or melt-spinning compared to those of the as-cast one. But in the spun then annealed alloy, the non-CaCu 5 phases disappeared and only a single-phase with CaCu 5 type structure was found. For all the alloys, the cell volume was increased in an order of as-cast

Implant-associated infection remains a difficult medical problem in orthopedic surgery. Therefore, the development of multifunctional bone implants for treating infection and regenerating lost bone tissue, which may be a result of infection, is important. In the present study, we report the fabrication of enoxacin-loaded poly (lactic-co-glycolic acid) (PLGA) coating on porous magnesium scaffold (Enox-PLGA-Mg) which combine the favorable properties of magnesium, the antibacterial property and the effect of inhibition of osteoclastic bone resorption of enoxacin. The drug loaded PLGA coating of Mg scaffold enables higher drug loading efficiency (52%–56%) than non-coating enoxacin loaded Mg scaffold (Enox-Mg) (4%–5%). Enox-PLGA-Mg exhibits sustained drug release for more than 14 days, and this controlled release of enoxacin significantly inhibits bacterial adhesion and prevented biofilm formation by Staphylococcus epidermidis (ATCC35984) and Staphylococcus aureus (ATCC25923). Biocompatibility tests with Balb/c mouse embryo fibroblasts (Balb/c 3T3 cells) indicate that PLGA-Mg has better biocompatibility than Mg. Finally, we also demonstrate that Enox-PLGA-Mg extract potently inhibited osteoclast formation in vitro. Therefore, Enox-PLGA-Mg has the potential to be used as a multifunctional controlled drug delivery system bone scaffolds to prevent and/or treat orthopedic peri-implant infections.

Although being an essential trace element required for human body health, Cu has long been seriously considered toxic when its amount exceeds certain limitation, which significantly limited the wide application of Cu in biomaterials. However, more and more bio-functions and benefits of Cu were found and confirmed, attracting the attention from biomaterials researchers in recent years. People have tried to immobilize Cu into biomaterials by various ways, in order to develop novel bio-functional Cu containing biomaterials with better bio-adaptions, and several different bio-functions of them have been demonstrated. This paper makes a review of the development of novel bio-functional Cu containing biomaterials, and focuses on their unique roles in enhancing bio-adaption of biomedical materials, including antibacterial performance, stimulating angiogenesis, promoting osteogenesis and inhibition of in-stent restenosis, aiming at proposing a prospective development direction for biomedical materials with better bio-adaptions.

This document is the Accepted Manuscript of the following article: Li Nan, Guogang Ren, Donghui Wang and Ke Yang, ‘Antibacterial Performance of Cu-Bearing Stainless Steel against Staphylococcus aureus and Pseudomonas aeruginosa in Whole Milk’, Journal of Materials Science and Technology, Vol 32(5): 445-451, May 2016, doi: http://dx.doi.org/10.1016/j/jmst.2016.01.0002. This manuscript version is made available under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License CC BY NC-NC 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited, and is not altered, transformed, or built upon in any way.