Search

Pure titanium is an ideal material for tissue replacements and implant materials for its superior biocompatibility and corrosion resistance, but its limited strength remains a major obstacle to its wide applications. A promising strategy for enhancing the strength is to alloy the pure titanium with oxygen. Herein, we reported an oxygen solid solution strengthening for pure titanium by achieving a titanium-oxygen (Ti–O) alloy using ball milling (BM) and spark plasma sintering (SPS). The effect of oxygen contents, ranging from 0.33 to 2.08 wt%, on the mechanical properties of pure titanium was systematically investigated. Experimental results indicate that the Ti–O alloy with the oxygen content of 1.95 wt% reached an ultrahigh yield strength of 2026 MPa and showed a large ductility of 11.2% in compression. According to the quantified analysis of strengthening mechanisms, solid solute oxygen atoms are responsible for the balance of superior yield strength and ductility of the Ti–O alloys. • The titanium-oxygen (Ti–O) alloys with ultrahigh strength and excellent ductility were prepared by ball milling and spark plasma sintering processes without any precious elements or heat treatment. • Outstanding properties of Ti-1.95O alloys are achieved with an ultrahigh compressive yield strength of 2026 MPa and good ductility of 11.2%. • The Ti-1.95O alloy overcomes the strength-ductility dilemma, resulting in the unexpected and dramatic increase in the ductility accompanied by increasing strength. [ABSTRACT FROM AUTHOR]

Biodegradable metallic glasses are used as disposable green devices whose constituents decompose into harmless byproducts, leaving no residual waste and requiring no removal surgery. Here, the large size Ca-based (Ca 65 Mg 15 Zn 20) bulk metallic glasses (BMGs) were fabricated by consolidating gas-atomized metallic glassy alloy powder using a spark plasma sintering (SPS) technique. The effects of sintering temperature on structure, mechanical properties, and biodegradation rate of the developed Ca-based BMGs in Hank's solution were evaluated. The high-strength consolidated samples with a fully glassy phase and suitable biodegradation rate were produced by the SPS process at a sintering temperature of 120 °C with a loading pressure of 600 MPa. The Ca–Mg–Zn bulk metallic glass alloys developed by the SPS process can offer excellent properties and satisfy large sample-size requirements, which opens possibilities of application as biodegradable materials. • The large-size degradable Ca-based (Ca 65 Mg 15 Zn 20) bulk metallic glasses (BMGs) with good strength of 226 MPa were prepared by spark plasma sintering process. • This process produced Ca 65 Mg 15 Zn 20 BMGs exhibit best mechanical properties and degradable rate when the sintering temperature was set to 120 °C. • Crystal phases appeared in the Ca 65 Mg 15 Zn 20 BMGs with increasing the sintering temperature, resulting in the decrease in the strength and corrosion resistance. [ABSTRACT FROM AUTHOR]

The high strength and low cost of titanium alloys have led to the development of these alloys for aerospace applications. In this study, ultra-high-strength Ti–N alloys were fabricated by ball-milling (BM) and spark plasma sintering (SPS), and the effects of the nitrogen content on the microstructure and mechanical properties of the alloys were studied. TiN powder was used as the raw material for doping the alloys with N atoms, and the N content was controlled by tuning the amount of TiN powder added. The yield strength of the Ti–N alloys increased with an increase in the N content and surpassed 2000 MPa when the N content reached 2.66 wt%. Quantitative analysis using the Hall-Petch equation and Labusch model demonstrated that fine-grain strengthening and solution strengthening worked in synergy to enhance the strength of the Ti–N alloys. The ultra-high-strength Ti–N alloys can be applied in the aerospace field for structure use, such as aircraft engines, fasteners, and burn-resistant materials. The preparation of novel Ti–N alloys validates the theoretical application of ubiquitous elements in titanium alloys. • The fully dense Ti–N alloys were fabricated successfully by one-step consolidation process via SPS technology. • Ultra-high yield strength Ti–N alloy of 2012 MPa was achieved when the N content was 2.66 wt%. • The quantitative analysis revealed the main strengthening mechanisms of the Ti–N alloys were solution strengthening and fine-grained strengthening. • The fracture mode affecd by the nitrogen of the titanium alloys was studied. microporous polymeric and cleavage. [ABSTRACT FROM AUTHOR]

A novel high-strength conductive Cu-based composite, utilizing AlCrCuFeNi 2.5 (Ni2.5) high-entropy alloy particles as the reinforcing phase, is synthesized through a combination of ball milling and spark plasma sintering processes. The mechanical and electrical properties of the composites are optimized by adjusting the composition. Under the synergistic effect of multiple strengthening mechanisms, the fabricated Cu-20 wt% Ni2.5 composites achieve an exceptional compressive strength of 920 MPa while maintaining an electrical conductivity of 44.3 % IACS (International Standard Copper Standard). The establishment of robust interface bonding between Ni2.5 reinforcement and Cu matrix stands as a pivotal assurance for the holistic performance of composites. Ni2.5 HEA is distinguished by good plasticity and high strength compared with traditional brittle reinforcements. An insight into the differences brought about by the distinctive dual-phase structure in terms of interfacial bonding, crack propagation, and performance is provided. It paves the way for selecting and projecting the composites for electrical contact applications, ushering in a realm of fresh possibilities. [ABSTRACT FROM AUTHOR]

[Display omitted] • Metallic glass (MG)-particle-reinforced nanocrystalline CuCrZr alloys with ultrahigh strengths and good conductivities are synthesized via mechanical milling and spark plasma sintering. • Outstanding properties of composites are achieved with ultimate compressive strengths of 1099 ± 33 MPa and 1185 ± 29 MPa and high conductivities of 29.9 ± 0.8% IACS and 25.2 ± 0.6% IACS, respectively. • The strengthening and conductivity mechanisms of the composites are discussed to analyze the excellent mechanical and electrical properties. Metallic glass (MG)-particle-reinforced nanocrystalline CuCrZr alloys with ultrahigh strengths and good conductivities are designed and synthesized via mechanical milling and spark plasma sintering (SPS). The particle morphology and dispersion state of the CuZrAl MG reinforcement in the CuCrZr alloy matrix are optimized by regulating the milling time of the composite powders prior to SPS consolidation. Outstanding properties are achieved by 5 h and 10 h milling processes with ultimate compressive strengths of 1099 ± 33 and 1185 ± 29 MPa and high conductivities of 29.9 ± 0.8% IACS and 25.2 ± 0.6% IACS, respectively. According to the quantified results of strengthening and conductivity mechanisms, MG reinforcements and ultrafine grains are responsible for the balance of superior strength and conductivity of the composites. [ABSTRACT FROM AUTHOR]