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Purpose: In recent years, the application of restorations and fixed dental prostheses to molars by computer-aided design-computer-aided manufacturing (CAD/CAM) with composite resin has been increasing. Titanium and titanium alloy having a high tissue affinity and good biocompatibility are suitable for cases where CAD/CAM fabrications are inadequate, such as allergic reaction to metal. Many studies have reported methods of production with titanium and titanium alloys. The purpose of this review is to survey the clinical application of titanium and titanium alloy restorations and fixed dental prostheses with various fabrication systems., Study Selection: A literature search in PubMed was performed for various fabrication systems of titanium and titanium alloy from 2010 through 2019. The search keywords were "titanium", "titanium alloy", "CAD/CAM", "cast", "fabrication system", "marginal gap", "internal gap", and "clinical performance". Only relevant studies are summarized and discussed in this review., Results: With any fabrication system, titanium and titanium alloy restorations and fixed dental prostheses fabricated with various systems were within the clinically acceptable ranges of marginal gap and internal fit. Additionally, these restorations were considered to have less effect on the periodontal issues. Although metal-ceramic restoration has clinical performance problems, such as ceramic fracture, fabrications with only titanium and titanium alloy were reported to have good clinical performance., Conclusions: Regardless of the fabrication system, titanium and titanium alloy restorations and fixed dental prostheses can be applied clinically. Titanium and titanium alloys are thought to be a promising alternative to the dental metals currently used., (Copyright © 2019. Published by Elsevier Ltd.)

[Display omitted] • A novel high Zn Al alloy is processed via two-step thermo-mechanical treatments. • A dense distribution of η' precipitates is achieved due to the unique processing. • A superhigh ultimate tensile strength up to 789 MPa is attained. Precipitation strengthening is crucial for the high strength of Al-Zn-Mg-Cu (7xxx) alloys. In this study, we synthesized a novel high-Zn 7xxx Al alloy through a comprehensive two-step thermo-mechanical treatment that includes hot extrusion and hot rolling. This approach effectively mitigates casting defects caused by high Zn content and preserves a significant number of dislocations and low-angle grain boundaries. These deformation substructures, coupled with high Zn concentrations, promote the dense formation of η' nanoprecipitates. As a result, this alloy exhibits an exceptional combination of mechanical properties, with an ultimate tensile strength (UTS) of 789 MPa and a tensile elongation of 9.2 %. Our findings offer innovative insights into the design of ultra-strong and ductile Al alloys for advanced engineering applications. [ABSTRACT FROM AUTHOR]

• Mechanism responsible for the anomalously severe HCS of Al-Li alloys were investigated. • Strong strain localization resulting from Li-rich inclusions induces microcrack initiation. • Liquid refilling is impeded by Li-rich inclusions occupying the interdendritic channels. This work reports a new mechanism for the severe hot cracking susceptibility (HCS) of cast Al-Li alloys. In contrast to the narrow vulnerable solidification temperature range increasing cracking resistance, alloys with high Li content or solute content, which are supposed to show lower HCS, instead exhibit anomalously high HCS. Results reveal that this phenomenon arises from a variety of Li-rich inclusions distributed in the interdendritic paths, including Li 2 O, LiAlO 2 , Li 2 CO 3 and LiH. These particles can form spontaneously with O 2 , CO 2 and H 2 O during solidification, deteriorating the interfacial bonding capacity. Meanwhile, the occupation of refilling channels for residual liquid increases the potential risk of microcrack initiation. These unfavorable factors promote the rapid propagation of cracks from the casting surface inward, which eventually leads to catastrophic fractures. [ABSTRACT FROM AUTHOR]

• Zn-Al alloy and Zn-Al/ZrB 2 composites were fabricated by liquid metallurgy route. • Addition of ZrB 2 particles to the composite results in significant grain refinement, • Heat treatment at 250 °C for 3 h resulted in a refinement of grain structure and hardness improvement. • Higher heat treatment temperatures led to increased grain size and reduced hardness. This study explores the impact of heat treatment on Zn-Al alloy and Zn-Al/ZrB 2 composites. Specifically, heat treatment at 250 °C for 3 h resulted in a significant refinement of grain structure and notable hardness improvement, showcasing an optimal combination of microstructural and mechanical properties. However, higher temperatures led to increased grain size and reduced hardness for both alloy and composites. These findings offer promising insights for optimizing processing parameters, enhancing the performance of Zn-Al based composites in critical engineering applications. [ABSTRACT FROM AUTHOR]

This study investigated the impact of the equal channel angular pressing (ECAP) combined with heat treatments on the microstructure and mechanical properties of AlSi10Mg alloys fabricated via selective laser melting (SLM) and gravity casting. Special attention was directed towards determining the effect of post-fabrication heat treatments on the microstructural evolution of AlSi10Mg alloy fabricated using two different routes. Three initial alloy conditions were considered prior to ECAP deformation: (1) as-cast in solution treated (T4) condition, (2) SLM in T4 condition, (3) SLM subjected to low-temperature annealing. Light microscopy, transmission electron microscopy, X-ray diffraction line broadening analysis, and electron backscattered diffraction analysis were used to characterize the microstructures before and after ECAP. The results indicated that SLM followed by low-temperature annealing led to superior mechanical properties, relative to the two other conditions. Microscopic analyses revealed that the partial-cellular structure contributed to strong work hardening. This behavior enhanced the material's strength because of the enhanced accumulation of geometrically necessary dislocations during ECAP deformation. [ABSTRACT FROM AUTHOR]

• Functionally graded unidirectionally solidified (FGDS) Al-33Cu eutectic alloy was produced. • The mean interlamellar spacing and the volume fraction of eutectic Al 2 Cu were controlled in centrifugal casting. • The hardness of FGDS Al-33Cu eutectic alloy gradually decreased from 183 HB to 155 HB in 75 mm section length. To produce a functionally graded and directionally solidified (FGDS) structure, an Al-33Cu eutectic alloy has been centrifugally cast into a bar-shaped steel mold using a vacuum centrifugal casting system. Uni-dimensional cooling was performed to obtain directional solidification. Microstructural characterizations were carried out on the longitudinally sectioned cast bar along the solidification direction. Results showed that the Al 2 Cu eutectic lamellar spacing varied between 0.32 µm and 1 µm from the outer region to the inner region of the cast bars along a 75 mm distance. Centrifugal casting has resulted in microsegregation of copper concentration in a range between 55.8 % and 53.9 % from the outer region to the inner region, respectively. Similarly, the volume fraction of the Al 2 Cu eutectic has also varied between 45.3 % and 53.7 %. This leads to a significant variation in the hardness of the FGDS Al-33Cu eutectic alloy from 183 HB to 155 HB from the outer region towards the inner region. [ABSTRACT FROM AUTHOR]

• A casting eutectic high entropy alloy Ni 30 Co 30 Cr 10 Fe 10 Al 18 W 2 was designed and prepared. • The alloy consists of soft FCC and hard B2 eutectic phases with the semi-coherent interface. • The alloy possesses a tensile strength of 1266.5 MPa and an elongation of 20.3% in the as-cast condition. Mechanical properties of casting alloys are generally limited. To make casting alloys applicable for a high level of service environments, a novel casting eutectic high entropy alloy (EHEA) with excellent mechanical properties is proposed. The hierarchical microstructures are with fine regular lamellar eutectic and coarse irregular eutectic. The eutectics consist of face-centered cubic (FCC) and ordered body-centered cubic (B2) phases with the semi-coherent interface. In the as-cast state, it shows a tensile strength of 1266.5 MPa and elongation of 20.3%. The unusual as-cast properties make it possible to manufacture high performance products by direct casting. [ABSTRACT FROM AUTHOR]

An NbC-Fe composite powder was synthesized from an Nb2O5/Fe/C mixture by electrochemical reduction and subsequent carbonization in molten CaCl2-NaCl. The composite has a core-shell structure, in which NbC acts as the cores distributing in the Fe matrix. A strong bonding between NbC and Fe is benefit from the core-shell structure. The sintering and electrochemical reduction processes were investigated to probe the mechanism for the reactions. The results show that NbC particles about several nanometers were embraced by the Fe shell to form a composite about 100 nm in size. This featured structure can feasibly improve the wettability and sinterability of NbC as well as the uniform distribution of the carbide in the cast steel. By adding the composite into steel in the casting process, the grain size of the casted steel was markedly deceased from 1 mm to 500 μm on average, favoring the hardening of the casted steel. [ABSTRACT FROM AUTHOR]

A novel casting TiAl alloy with fine homogeneous microstructure and excellent performances is obtained assisted by the ultrasonic melt treatment. The coarse columnar crystal is modified into non-dendritic structure and the large grain is refined from 3098 μm to 88 μm; the micro-segregation, micro-porosities and precipitates are eliminated as well. After ultrasonic melt treatment for 90 s, the highest compressive strength is improved up to 1705 MPa, about 12% higher than the “quasi-oriented” TiAl alloy. [ABSTRACT FROM AUTHOR]

• A new AlCrFeMnNi 2 HEA with a unique sunflower-like eutectic structure was designed. • The HEA has excellent comprehensive mechanical properties. • Coherent interface and bimodal distribution of B2 phase lead to good properties. Although most BCC-based high-entropy alloys have high strength and excellent high temperature mechanical properties, their low plasticity greatly limit their application. It is a new challenge to develop new BCC-based high-entropy alloys with excellent combination of high strength and plasticity. In this study, we prepare a new BCC/B2 AlCrFeMnNi 2 high-entropy alloy with a unique sunflower-like eutectic microstructure. This alloy has a high yield strength of 1206 MPa, a high fracture strength of 3437 MPa and large compressive plastic strain of 37.5%. The excellent compressive mechanical properties are superior to many other BCC/B2 high-entropy alloys. These properties can be attributed to its unique microstructure consisting of coherent interface between BCC and B2 phase and the bimodal distribution of the B2 precipitates. Our results can provide a meaningful reference for improving the plasticity of BCC-based high entropy alloys. [ABSTRACT FROM AUTHOR]

In this paper, casting and ball milling procedures were used to create the quaternary alloy La 7 Sm 3 Mg 80 Ni 10 , and the structural evolutions during hydrogen sorption and desorption were investigated and described. According to the findings, ball milling lowers the size of grains and particles while also altering their surface properties. The as-cast alloy absorbs 4 wt% H 2 in 118, 67, and 58 s at 473, 533, and 553 K, respectively, whereas the as-milled alloy takes 108, 56, and 50 s. Additionally, the first hydrogen release temperature of the alloys as-cast and as-milled are 553.9 and 547.4 K, respectively. The as-milled and as-cast alloys had absolute values of the dehydrogenation enthalpy change (Δ H) of 77.13 and 76.52 kJ/mol and apparent activation energies for dehydrogenation (E de) of 80.79 and 78.72 kJ/mol, respectively. • Compared the hydrogen storage property of as-cast and milled alloys. • Ball milling modified the surface state of alloy powders. • Particle size can be decreased by ball milling. • Ball milling decreased the dehydrogenation activation energy of alloys. [ABSTRACT FROM AUTHOR]

• A novel method combining vacuum purification and mechanical stirring was proposed. • The purification mechanism in A356 alloy melts was discussed under vacuum-stirring. • Tensile strength and ductility of A356 alloys was enhanced by vacuum-stirring. Vacuum purification technology that is dependent on the static pressure between liquid and gas is an effective method to acquire high-quality alloy melts. However, during purification, there is a low degassing efficiency. Here, a novel method combining vacuum purification with mechanical stirring was proposed to purify aluminum alloy melts. The results showed that compared with the vacuum purification, the hydrogen content decreased from 0.12 to 0.08 ml/100 g; the yield strength, tensile strength and elongation increased by 51.3 %, 33.4 % and 114.8 %, respectively, in the A356 alloy subjected to the vacuum-stirring purification. Furthermore, the purification mechanism related to bubbles was discussed in melts under vacuum-stirring. [ABSTRACT FROM AUTHOR]

• The excellent mechanical properties produced by refined grains can be inherited. • Strengthening mechanism of the as-cast and aged samples is changed. • Dislocation and precipitation strengthening play a dominate role in aged samples. In this investigation, a novel heredity phenomenon was reported that the mechanical properties of thermo-mechanically processed Cu-15Ni-8Sn alloys were improved by refining the as-cast structure. This underlying mechanism of hereditary strengthening was carefully analyzed, which is mainly contributed to the additional dislocation proliferation induced by structure refinement and accelerated precipitation effect on strengthening phases. The strengthening mode changed from grain refinement strengthening in as-cast state to dislocation strengthening and precipitation strengthening for aged alloys. [ABSTRACT FROM AUTHOR]

• Novel C-doped TiB 2 particles are introduced into an Al-Si-Mg alloy. • The average grain size of α-Al can be reduced by 70% via C-doped TiB 2 particles. • The C-doped TiB 2 particles enhance the strength-ductility synergy of A357 alloy. We report novel C-doped TiB 2 particles introduced into an Al-Si-Mg alloy. The impact of C-doped TiB 2 particles on the α-Al grain and associated mechanical properties were systematically investigated. These particles were introduced via a master alloy (Al-TBC master alloy, or Al-TBC for short). The results show that the C-doped TiB 2 particles have a dramatical nucleation capability for the α-Al grain, thus eliminating the grain refinement problem of Si "poisoning" in the A357 alloy (one typical category in Al-Si-Mg alloy). As a result, the average grain size of α-Al can be refined to 140 μm from 490 μm by adding 0.5 wt% Al-TBC. The C-doped TiB 2 particles can also enhance the strength-ductility synergy of A357 alloy at room temperature. At 0.5 wt% Al-TBC, the ultimate tensile strength, yield strength, and elongation of T6-treated A357 alloy are 370.1 ± 1.2 MPa, 302.5 ± 7.5 MPa, 12.38 ± 1.2 %, respectively. This work provides a novel prospect for resolving the problem of Si "poisoning" in grain refinement and strength-ductility trade-off in hypoeutectic Al-Si alloys via C-doped TiB 2 particles. [ABSTRACT FROM AUTHOR]

Microstructure and thermal properties of Mg-(3 mass% or 5 mass%) Sn-2 mass% Ca alloys as casts and extrusions have been investigated with different ram speeds and extrusion temperatures. Mg-(3 mass% or 5 mass%) Sn-2 mass% Ca alloys are composed of $$\upalpha $$ -Mg, MgSnCa, and $$\hbox {Mg}_{2}\hbox {Ca}$$ phases. By adding Sn content from 3 mass% to 5 mass%, the MgSnCa phase is increased and the $$\hbox {Mg}_{2}\hbox {Ca}$$ phase is decreased. During hot extrusion, the average grain sizes are increased with increasing ram speed and temperature. The ultimate tensile strength ( UTS) and elongation for the Mg-5Sn-2Ca alloy at $$2.3\, \hbox {mm}{\cdot }\hbox {s}^{-1}$$ are 227.73 MPa and 18.43 %, respectively. With increasing extrusion ram speed, the UTS and elongation for the Mg-5Sn-2Ca alloy are remarkably decreased to 215.95 MPa, 206.33 MPa, and 14.74 %, 6.88 %, respectively. The thermal conductivity for the Mg-3Sn-2Ca alloy is dramatically improved, compared to commercialized Mg alloys such as AZ31 and AZ91 due to formation of MgSnCa and $$\hbox {Mg}_{2}\hbox {Ca}$$ phases. [ABSTRACT FROM AUTHOR]

• The aging process of high strength Al-5 Mg-3Zn-1Cu cast alloy is optimized. • Double-step aging treatment shortened the aging time from 156 to 5 h. • The strengthening phase is fine and dispersed GP zones. • Double-step aging accelerates the growth of GP zones to achieve peak hardness. Al-5Mg-3Zn-1Cu cast alloy can obtain high mechanical properties by single-step aging treatment at 120 °C, but this process is inefficient due to aging time of 156 h. The double-step aging treatment at 120 °C for 1 h and then at 150 °C for 4 h significantly reduced the time, from 156 to 5 h to peak aging, and still achieved similar mechanical properties. The main strengthening phase of the alloy is fine and dispersed GP zones under both aging treatment processes. The double-step aging processing greatly improves the productivity in heat treatment of Al-5Mg-3Zn-1Cu cast alloys. [ABSTRACT FROM AUTHOR]

Abstract: To improve mechanical properties and particularly corrosion resistance of aluminum high pressure die castings, a new Al–Si based alloy was developed by lowering copper content and optimizing other alloying elements. In comparison with the widely used high pressure die casting A380 and A360 alloys, the newly developed alloy exhibits an improved strength by 20% with respect to A360 and a better corrosion resistance by 45% compared with A380. The improvement in mechanical properties and corrosion resistance of the new alloy is attributed to the dramatic microstructure refinement and eutectic silicon morphology modification with much better homogeneous distribution of the second phase particles in the matrix. [Copyright &y& Elsevier]

The improved halide salt route has been employed to produce Al-3B master alloys with different microstructures. The micro-structural features of AlB particles exhibited different impacts on the grain refining response of Al-7Si alloy, evolving with the holding time after inoculation. Large blocky AlB particles suffer from an intense fading effect while strip-like particles are not effective enough at the 0.005 wt% B addition level. Among the various Al-3B master alloys, sample 1 containing fine, blocky AlB particles was revealed to be the most efficient in refining Al-7Si alloy. With inoculation of only 0.005%B of such alloy, the final grain size of Al-7Si alloy can reach 238 μm. Its grain refining efficiency was more or less retained for holding times up to 60 min. [ABSTRACT FROM AUTHOR]

Abstract: The current work presents the room-temperature mechanical properties and the corrosion resistance in 3.5% NaCl solution of conventional casting and rapidly solidified Mg6ZnMn (ZM61) magnesium alloys. It is found that the mechanical properties of rapidly solidified ZM61 alloy are dramatically enhanced, with the ultimate strength increased from 335MPa to 460MPa (37% increment), which can be attributed to the formation of the refined dendrite microstructure and the strengthening MgZn2 phase distributed within the matrix. Furthermore, the rapidly solidified ZM61 alloy performs better in corrosion resistance than the extruded ZK60 and pure Mg alloys, suggesting that the rapid-solidification technique is a promising way to improve the strength and corrosion resistance of magnesium alloy for the structural and corrosive media utilization. [Copyright &y& Elsevier]

Abstract: A Mg–5wt.%Sc alloy was prepared by gravity casting technology. The microstructure, aging behaviour and mechanical properties were investigated. The alloy exhibited a significant age hardening response when it was aged at 190°C for 8h under an applied stress of 30MPa. Moreover, compared with the standard T6 condition (solid solution and artificial aging), an improved strength and higher elongation occurred simultaneously for the stress aged sample. The enhanced strength and elongation were chiefly related to the nanosize spherical-shaped MgSc precipitates which effectively decreased the stress concentration at the tip during the deformation. The action of the external stress field eliminated the anisotropy normally associated with the growth of the precipitates during the standard aging process, leading to the formation of spherical-shaped precipitate. It was revealed that the stress aging was an effective approach to the improvement of the mechanical properties of Mg–5wt.% Sc alloy and potentially many other Mg alloys. [Copyright &y& Elsevier]

The effect of the introduction of in-situ formed Nb-based compounds on Al-including Mg alloys has been investigated. It is found that grain refinement is consistently achieved. Nb-based intermetallic particles are responsible of the effective heterogeneous nucleation of Al-including Mg alloys. The refining mechanism is discussed on the base of crystallography. [ABSTRACT FROM AUTHOR]

• The formation mechanism of bifilm defect in Mg-Gd-Y-Zr alloy is revealed as surface Y 2 O 3 oxide film shrinkage. • The bifilm in Mg-Gd-Y-Zr alloy contains Zr-cores. • Microcracks resulted by the shrinkage of bifilm is elucidated responsible for the generation of Zr-core. Mg-Gd-Y-Zr alloy has excellent mechanical properties at room and high temperatures, but its high oxidation properties can also result in a significant number of bifilm defects. However, its formation mechanism was not revealed so far, which was explored in the present work. The results showed that the surface oxide film folds into a grid-like double layer structure defect during solidification, due to the difference of thermal expansion coefficient between surface oxide film and matrix. In addition, the oxide film produces microcracks. As the magnesium alloy melt fills the crack, Zr precipitates into crystal nucleus with peritectic reaction and Y 2 O 3 accumulates. These results would shed new lights on the understanding of shrinkage formation of bifilm defects and improving the defects control of magnesium alloy castings. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we show that the Bauschinger effect is intimately tied not only to plasticity as is historically understood but to the damage state as well. We illustrate the plasticity and damage influence on the Bauschinger effect by employing different definitions (Bauschinger stress parameter, Bauschinger effect parameter, the ratio of forward-to-reverse yield, and the ratio of kinematic-to-isotropic hardening) for two differently processed aluminum alloys (rolled and cast) in which specimens were tested to different prestrain levels under tension and compression. Damage progression from second phase particles and inclusions that were generally equiaxed for the cast A356-T6 Al alloy and elongated for the rolled 7075 Al alloy was quantified from interrupted experiments. Observations showed that the Bauschinger effect had larger values for compression prestrains when compared to tension. The Bauschinger effect was also found to be a function of damage to particles/inclusions, dislocation/particle interaction, and the work hardening rate. [Copyright &y& Elsevier]

In order to improve the electrochemical performances of La–Mg–Ni system (PuNi3-type) hydrogen storage alloy, a trace of B was added in La2Mg(Ni0. 85Co0. 15)9 alloy. La2Mg(Ni0. 85Co0. 15)9B () hydrogen storage alloys were prepared by casting and rapid quenching. The electrochemical charging-discharging cycling lives and microstructures of the as-cast and quenched alloys were measured and analyzed. The effects of B additive on the microstructures and cycling lives of as-cast and quenched alloys were investigated in detail. The results show that the as-cast and quenched alloys are composed of the (La, Mg)Ni3 phase (PuNi3 structure), the LaNi5 phase and the LaNi2 phase. A trace of the Ni2B phase exists in the as-cast alloys containing B. The Ni2B phase in the alloys containing B nearly disappears after rapid quenching and the relative ratio of each phase in the alloys changes with the variety of the quenching rate. The addition of B obviously enhances the charging-discharging cycling stabilities of the as-cast and quenched alloys. When B content increases from 0 to 0. 2, the cycling lives of the as-cast and quenched at 20m/s alloys were increased from 72 to 94 cycles and from 86 to 104 cycles, respectively. [Copyright &y& Elsevier]

Abstract: The damping capacity of as cast Mg–9Al–Si alloys was investigated. A damping peak exhibits at around 420K for a frequency of about 1Hz and it was correlated to the characteristic grain boundary peak of magnesium. The activation energy of damping peak is lower than self-diffusion activation energy of pure magnesium, but higher than activation energy of AZ91 reported. The effect of measurement conditions including strain amplitude, heating rate and consecutive measurement number on damping peaks has also been discussed. [Copyright &y& Elsevier]

Abstract: In order to refine the cast microstructure and improve the mechanical property of TiAl alloy, the element of Cr was chosen for alloying. Experimental results show that the refinement was achieved and the cast microstructure was controlled to be fine by inducing β solidification due to the addition of a high content of Cr. Furthermore, the cast microstructure was optimized to be a fine fully lamellar (FL) one by one-step heat treatment. And with the microstructure refinement and optimization, the tensile strengths of the present cast alloys both at room and high temperatures were improved to exceed the strength level for traditional cast TiAl alloys, and reached that for wrought TiAl alloys. [Copyright &y& Elsevier]

A novel approach, the heat treatment of liquid metal, was initiated to investigate the possibility of removing oxide films and primary intermetallics from aluminum melts and its effectiveness. The concept was to remove oxide cracks from liquid metal by precipitation of primary intermetallics onto oxide films, causing them to sink under the weight of the particles. The sedimentation of primary a-Fe particles was investigated at 600uC using an Al-11.1Si-0.4Mg alloy. The liquid metal quality was assessed by reduced pressure and pressure filtration tests. After sedimentation processing there is a clear improvement in liquid metal quality due to the sedimentation and separation of primary a-Fe particles, causing the removal of some oxide films from aluminum melts. Thus the heat treatment of liquid metal has the potential to improve liquid metal quality. Primary a-Fe phase seems to precipitate onto the wetted sides (i.e. the outer interfaces) of double oxide films. However, the gap between the two dry sides of a double .lm constitutes a crack, thus explaining the common observation of cracks in and around such intermetallics. Hydrogen precipitation into the central oxide films in intermetallics may open the oxide films, or even expand and convert the cracks into open porosity. The oxide films may further open during a later stage of freezing because of shrinkage and cooling stress in the solid state. [ABSTRACT FROM AUTHOR]

[Display omitted] • Evolution of hyper-branch cast structure during thermomechanical processing. • Proposing a new micro-mechanism and conceptual model for dendrite fragmentation. • Greatly contribution of substructure development in disintegration of the dendrites. The present work deals with emphasizing the role of substructure development in fragmentation of the cast structure in Mg-Sn-0.3Li-3Zn alloy during thermomechanical processing. In this respect, a new micro-mechanism and a conceptual model were proposed for dendrite fragmentation, which was supported by 3D-tomography, electron back scattered diffraction, and angle selective back-scattered imaging analyses. Balancing of the dihedral angle of the non-equilibrium triple junctions led to the formation of grooves at the dendrite arms, followed by penetration of α-Mg matrix through the grooves and finally resulted in fragmentation of the specified dendrite arm. In fact, despite the conventional expectation regarding the high contribution of brittle fracture and shearing in fragmentation of the dendrites at low temperature regime, it was observed that the substructure development in a medium-to-high stacking fault energy material greatly participated in thermally-activated disintegration of the dendritic cast-structure. [ABSTRACT FROM AUTHOR]

A non-equiatomic Ni 3.5 Co 3 Cr 1.5 medium-entropy alloy (AT0) with a single-phase face-centered cubic structure (FCC) directly obtained by arc-melting shows the low yield strength of 147 MPa, ultimate tensile strength of 447 MPa and large total elongation to fracture of 78.8%. By doping Al and Ti, the as-cast (Ni 3.5 Co 3 Cr 1.5) 90 Al 5 Ti 5 high-entropy alloy (AT5) exhibits enhanced strength-ductility synergy. Compared to AT0 alloy, the yield strength of AT5 alloy increases more than fivefold to 792 MPa, ultimate tensile strength doubles to 1004 MPa, and still remaining a high elongation of 38.2%. The apparent increase in strength can be attributed to uniformly distributed, high-content, conherent (Ni,Co) 3 (Al,Ti)-type nanoprecipitates formed in FCC matrix. The formation of various dislocation substructures and crossed stacking faults (SFs) with Lomer-Cottrell locks during tensile deformation is responsible for strain hardening of AT5 alloy. [Display omitted] [ABSTRACT FROM AUTHOR]

• A novel Zn–Fe–P master alloy has been prepared and the P–rich phase is Zn 3 P 2. • The Zn 3 P 2 phase will in–situ transfer into AlP in Al–18Si melt. • The master alloy exhibits better modification performance than Al–Fe–P and Fe–P. • The Zn–Fe–P master alloy is suitable for application in low pressure casting industries. A novel Zn–7Fe–3P master alloy has been synthesized in this paper, by promoting the reaction of Fe–30P alloy with Zn melt. The phosphide in the master alloy is Zn 3 P 2 , which will be in–situ transferred into AlP when it is applied to refine primary Si of A390 alloy at 720 °C. Compared with Fe–30P and Al–7Fe–3P, the Zn–7Fe–3P master alloy exhibits the best refining performance. The underlying mechanism was discussed based on thermodynamic analysis. The Zn–7Fe–3P master alloy is regarded promising for application in low pressure casting industries. [ABSTRACT FROM AUTHOR]

• Nano-treating on eutectic Al-33.2Cu and hypereutectic Al-20Mg 2 Si alloys were investigated. • Both primary and eutectic phases have been modified by nano-particle clusters. • The confined space in the particle clusters is responsible for nano-treating. In this work, an Al-Al 2 O 3 -ZrB 2 master alloy was applied to nano-treat eutectic Al-33.2Cu and hypereutectic Al-20Mg 2 Si alloys. The (Al 2 O 3 + ZrB 2) particle clusters were detected in these alloys. The Al 2 Cu eutectics inside of the particle clusters are much coarser than the lamella shaped Al 2 Cu in the initial alloy. The primary Mg 2 Si and labyrinthic eutectics have been transformed into fragmentary and intermittent, respectively. The confined space inside of the particle clusters are supposed responsible for the nano-treating performance through affecting the solute diffusion process and phase growth procedure. [ABSTRACT FROM AUTHOR]

• The microstructures of novel cast Al–4.5Cu–3.5Zn–0.5 Mg alloy were investigated. • Ω phases and θ′ phases were the main phases in the aged alloy. • Interrupted aging led to a fine highly dense Ω phase and θ′ phase. • The mechanical properties of cast alloy were enhanced under interrupted aging. This study investigated the microstructure and mechanical properties of interrupted aged cast Al–4.5Cu–3.5Zn–0.5 Mg alloy. Small Cu-rich Guinier–Preston (GP) zones and Mg-rich clusters (GPI zones) formed during the initial aging stages. Zn addition promoted the formation of a uniformly dispersed fine plate-like Ω phases in the matrix. The microstructure of the interrupted aged alloy comprised fine highly dense Ω and θ′ phases within the matrix, compared to that of isothermal aged alloy. The enhanced mechanical properties of the cast Al–4.5Cu–3.5Zn–0.5 Mg alloy were attributed to this microstructure. [ABSTRACT FROM AUTHOR]

• Difference of borides in alloys based on 304 and 316 stainless steels was found. • Borides of M 2 B are present in the former alloy, with M 2 B and M 3 B 2 in the latter. • M 3 B 2 borides promote the connectivity of the entire borides in the latter alloy. • The latter alloy was cracked during hot rolling due to the interconnected borides. High boron alloys containing 2.0 wt% B based on 304 and 316 stainless steels, respectively, were prepared by vacuum arc melting method. Hot rolling was conducted to measure the workability of the two types of high boron alloys. M 2 B borides of long stripy and blocky shape are presented randomly over the matrix in the as-cast alloy based on 304 stainless steel. In addition to the M 2 B borides, Mo-rich M 3 B 2 borides are formed and they promote the connectivity of the borides in the as-cast alloy based on 316 stainless steel. The alloy based on 304 stainless steel has well hot workability, whereas the alloy based on 316 stainless steel was severely cracked during the hot rolling process. [ABSTRACT FROM AUTHOR]

The microstructural characteristics and Young's modulus of the as-cast Ti–15Ta–15Nb alloy are reported in this study. On the basis of the examined XRD and TEM results, the microstructure of the current alloy is essentially a mixture (α + β+ α′ + α″ + ω + H) phase. The new H phase has not previously been identified as a known phase in the Ti–Ta–Nb alloy system. On the basis of examination of the Kikuchi maps, the new H phase belongs to a tetragonal structural class with lattice parameters of a = b = 0.328 nm and c = 0.343 nm, denoting an optimal presentation of the atomic arrangement. The relationships of orientation between these phases would be {0001}α//{110}β//{ 1 ¯ 2 1 ¯ 0}ω//{10 1 ¯ }H and (01 1 ¯ 0)α//(1 1 ¯ 2)β//( 1 ¯ 010)ω//(121)H. Moreover, the Young's modulus of the as-cast Ti–15Ta–15Nb alloy is approximately E = 80.2 ± 10.66 GPa. It is implied that the Young's modulus can be decreased by the mixing of phases, especially with the presence of the H phase. [ABSTRACT FROM AUTHOR]

• Near-liquidus extrusion casting AZ91D alloy was studied for the first time. • The lower the temperature near the liquidus, the finer the grain size. • The lower the casting temperature, the more uniform the microstructure. • The near liquidus extrusion casting can improve the properties of AZ91D alloy. The effect of near-liquidus squeeze casting temperature on microstructure and mechanical property of AZ91D alloy differential support was studied. By increasing the pouring temperature, the grain size of die casting AZ91D alloy differential support increased, the grain morphology changed from spherical equiaxed grain to equiaxed dendrite, and the β-Mg 17 Al 12 phase changed from fine uniform distribution to large-area segregation. Furthermore, with the increase of pouring temperature, the tensile strength and elongation of the AZ91D alloy differential support both decreases. [ABSTRACT FROM AUTHOR]

• A new aluminium alloy was cast from recycled beverage can (RBC) using stir casting method. • Precipitation hardening and artificial aging treatments were done at 475 °C and 145 °C respectively. • Postmortem of the nature of fracture and substrates was conducted. • Peak yield strength (σ y) of 117.200 MPa and least of 51.212 MPa were recorded with an average extension (e) of 0.197 mm. The aim of this letter was to conduct a postmortem on the nature of fracture, substrates and possible precipitates formed in a novel experimental 7xxx alloy cast from recycled beverage cans (RBCs) and link same to yield strength (σ y) following heat treatment (HT). Fractographic investigation revealed the formation of dendrites and hardening phases such as MgZn 2 and Al 2 Mg 3 Zn 3 among others, following HT. An alloy S10 recorded the peak σ y of 117.200 MPa while S3 was the least with 51.212 MPa and extension (e) of 0.197 mm. [ABSTRACT FROM AUTHOR]

Cast austenitic heat-resistant steels are attractive candidates for ultra-high temperature applications, owing to their relatively high strengths and low costs. In the present study, a new alloy was developed with improved mechanical properties at 1000 °C based on two commercial cast austenitic heat-resistant steels. The alloy composition was designed by predicting the quantities of different precipitates in these steels under the equilibrium and non-equilibrium conditions through the CALPHAD method. The new steel exhibited much better creep resistance than the commercial ones at 1000 °C, despite of the similar tensile strengths. It was strongly attributed to the increased Nb content that accelerated the precipitation of the "Chinese-script" Nb(C,N) and strengthened the interdendritic regions. The W addition was completely removed to prevent the formation of the residual δ-ferrite and Cr 23 C 6 that accelerated the propagation of cracks and degraded the mechanical properties. A small addition of N was also demanded to reduce the quantity of the residual δ-ferrite and brittle intermetallic phases, but its content should be strictly limited to avoid the precipitation of Cr 2 N. Based on this alloy design, the reliability of the CALPHAD method is well experimentally confirmed by comparing the phases in the microstructure of the commercial and new steels. [ABSTRACT FROM AUTHOR]