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Friction stir welding (FSW) was introduced to join laser powder bed fusion (LPBF) AlSi10Mg alloys in this study. Microstructure and texture evolution, microhardness distribution and tensile properties of the FSW joints were investigated. The evolution of grain size, grain boundary and misorientation angles distribution, dynamic recrystallization and crystallographic texture in various regions of the FSW joint concerning base metal (BM), thermo-mechanically affected zone (TMAZ), upper part of nugget zone (UPNZ) and low part of nugget zone (LPNZ) was characterized by using electron back-scattered diffraction (EBSD). The analysis reveals a strong texture evolution of shear components on the TMAZ, UPNZ and LPNZ as well as a fully recrystallized grain structure on the UPNZ and LPNZ. Additionally, a gradual evolution in Si-rich eutectic from continuous cellular networks in the BM to totally globularized particles in the UPNZ and LPNZ occurs in the FSW joint. The microhardness rapidly decreases to the TMAZ from the BM through heat affected zone (HAZ) reaching the lowest value of ∼65.0 HV at the TMAZ/NZ boundary. The FSW joint in LPBF AlSi10Mg alloys exhibits an ultimate tensile strength (UTS) of 247 MPa and an elongation-to-failure (EI) of 8.8%. The UTS of FSW joints is reduced compared to the BM, but the EI has been increased by 160%, implying an improvement in tensile ductility. [Display omitted] • Friction stir welding was introduced to weld laser powder bed fusion AlSi10Mg. • New shear textures of F, R-Goss and R-Cube components are developed in the FSW joint. • LAGBs are increased in the TMAZ, and a high fraction of HAGBs is developed in the NZ. • FSW of LPBF AlSi10Mg results in a gradual evolution of Si-rich phase morphology in the joint. • FSW of LPBF AlSi10Mg produces the highest UTS of 247.0 MPa and the maximum EI of 8.8%. [ABSTRACT FROM AUTHOR]

Titanium-tantalum (Ti-Ta) alloy has excellent biomechanical properties with high strength and low Young's modulus, showing great application potential in the biomedical industry. In this study, Ti-Ta alloy samples were prepared by laser powder bed fusion (LPBF) technology with mixed pure 75 wt.% Ti and 25 wt.% Ta powders as the feedstock. The maximum relative density of Ti-Ta samples prepared by LPBF reached 99.9%. It is well-accepted that four nonequilibrium phases, namely, α′, α″ and metastable β phase exist in Ti-Ta alloys. The structure of α′, α″ and β are hexagonal close-packed (HCP), base-centered orthorhombic (BCO) and body-centered cubic (BCC), respectively. X-ray Diffraction (XRD) analysis showed that the α′ phase transformed to the α″ phase with the increase of energy density. The lamellar α′/α″ phases and the α″ twins were generated in the prior β phase. The microstructure and mechanical properties of the Ti-Ta alloy were optimized with different LPBF processing parameters. The samples prepared by LPBF energy density of 381 J/mm3 had a favorable ultimate strength (UTS) of 1076 ± 2 MPa and yield strength of 795 ± 16 MPa. The samples prepared by LPBF energy density of 76 had excellent ductility, with an elongation of 31% at fracture. [ABSTRACT FROM AUTHOR]

Zinc (Zn) alloys have recently revolutionized and shown promising usage for degradable biomedical implants (BMI). However, due to the low strength of pure Zn, its application in the biomedical industry was limited. In the current research, an innovative biodegradable Zn-0.4Li-0.4Cu alloy produced by laser powder bed fusion (LPBF) with good mechanical properties was investigated. The Zn-0.4Li-0.4Cu alloy showed superior mechanical properties (tensile strength at 296 MPa, yield strength at 260 MPa, and after heat treatment elongation at 8.3 %), a record for biodegradable Zn alloys, as a consequence of grain refinement, second-phase precipitation of intermetallic compounds, and solid solution strengthening. The impacts of Cu and Li on the microstructures, mechanical behaviors, corrosive behavior and deterioration rate of the Zn-0.4Li-0.4Cu alloy were studied. The addition of Cu and inherent fast-cooling rate of the LPBF process are favorable for promoting the nucleation events, leading to the refinement of grains. In addition, the formation of the second-phase precipitates (CuZn 4 and ZnLi 4) in the matrix was founded to further improve the mechanical properties. Moreover, the alloy showed a consistent degradation manner and a suitable degradation rate of 0.023 mm/year. Based on the findings shown above, the biodegradable Zn-0.4Li-0.4Cu alloy can be a potential candidate for vascular stents and medical applications due to its excellent mechanical properties and adequate degrading behavior. • The Zn-0.4Li-0.4Cu alloy produced by laser powder bed fusion (LPBF) demonstrated exceptional mechanical properties, with a tensile strength greater than 296 MPa, and elongation of 8.3 %. • The superior mechanical properties of the as-LPBF-built Zn-0.4Li-0.4Cu alloy can be attributed to the morphology and distribution of the intermetallic compounds and dislocations. • The novel biodegradable Zn-0.4Li-0.4Cu alloy is a promising candidate for fabricating degradable biomedical implants due to its strength, reasonable ductility, and satisfactory degradation rate. [ABSTRACT FROM AUTHOR]

In this work, the creep behaviors of the graphitic and graphite-TiB 2 composite as cathode materials have been investigated at high temperature aluminum electrolysis for discussing the role of TiB 2 particles in creep resistance and mechanical properties connected with the microstructural evolution involving electrolyte penetration and cracking. The graphite-TiB 2 composite has superior creep resistance over the graphitic sample. The corresponding creep strain can be as low as ~0.2% after the high temperature electrolysis. The addition of TiB 2 particles greatly densifies the prepared composite with low porosity, resulting in the reduction of penetrating channels. The well-wetted TiB 2 particles by liquid Al generate a protective dense Al layer on the surface of composite, greatly blocking the electrolyte penetration. In turn, liquid Al may slowly penetrate into the composite via the cracks formed channels. The fracture strength of the graphite-TiB 2 composite increases from 41.6 MPa to 48.9 MPa after creep test at high temperature loading. Such improved properties should be attributed to the combined mechanism with reduced micro-cracks, decreased penetrating channels and the reinforcement due to addition of TiB 2 particles. [ABSTRACT FROM AUTHOR]