In-situ bending and stretching were conducted on hot-rolled and annealed Ti/Al/Mg/Al/Ti laminates,with a focus on crack initiation and propagation of intermetallics and component layers,which helps to clarify their de...In-situ bending and stretching were conducted on hot-rolled and annealed Ti/Al/Mg/Al/Ti laminates,with a focus on crack initiation and propagation of intermetallics and component layers,which helps to clarify their deformation behavior and fracture forms.The results show that delamination is the early fracture form of laminate with or without intermetallics at Al/Mg interface,so Al/Mg interfacial bonding strength determines the mechanical properties of laminate.Various and irregular intermetallics cracks lead to Al/Mg interface delamination in annealed laminate and help to release stress.Necking and fracture of component layers are observed at the late deformation stage,and the sequence is Al,Mg and Ti layers,resulting from their strength.Angle between crack propagation direction and stretching direction of Mg layer both in rolled and annealed laminates is around 45°due to the effect of shear deformation,and crack convergence leads to final complete fracture of Mg layer.展开更多
Bacterial colonization of orthopedic implants is one of the leading causes of failure and clinical complexities for load-bearing metallic implants. Topical or systemic administration of antibiotics may not offer the m...Bacterial colonization of orthopedic implants is one of the leading causes of failure and clinical complexities for load-bearing metallic implants. Topical or systemic administration of antibiotics may not offer the most efficient defense against colonization, especially in the case of secondary infection, leading to surgical removal of implants and in some cases even limbs. In this study, laser powder bed fusion was implemented to fabricate Ti3Al2V alloy by a 1:1 weight mixture of CpTi and Ti6Al4V powders. Ti-Tantalum(Ta)–Copper(Cu) alloys were further analyzed by the addition of Ta and Cu into the Ti3Al2V custom alloy. The biological,mechanical, and tribo-biocorrosion properties of Ti3Al2V alloy were evaluated. A 10 wt.% Ta(10Ta) and 3 wt.% Cu(3Cu) were added to the Ti3Al2V alloy to enhance biocompatibility and impart inherent bacterial resistance. Additively manufactured implants were investigated for resistance against Pseudomonas aeruginosa and Staphylococcus aureus strains of bacteria for up to 48 h. A 3 wt.% Cu addition to Ti3Al2V displayed improved antibacterial efficacy, i.e.78%–86% with respect to CpTi. Mechanical properties for Ti3Al2V–10Ta–3Cu alloy were evaluated, demonstrating excellent fatigue resistance, exceptional shear strength, and improved tribological and tribo-biocorrosion characteristics when compared to Ti6Al4V. In vivo studies using a rat distal femur model revealed improved early-stage osseointegration for alloys with10 wt.% Ta addition compared to CpTi and Ti6Al4V. The 3 wt.% Cu-added compositions displayed biocompatibility and no adverse infammatory response in vivo. Our results establish the Ti3Al2V–10Ta–3Cu alloy’s synergistic effect on improving both in vivo biocompatibility and microbial resistance for the next generation of load-bearing metallic implants.展开更多
基金financially supported by Shanxi provincial Youth Fund(No.201801D221101)the National Natural Science Foundation of China(Nos.52005362,U1810208,U1710254)Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi,China(Nos.2019L0149,2019L0994)。
文摘In-situ bending and stretching were conducted on hot-rolled and annealed Ti/Al/Mg/Al/Ti laminates,with a focus on crack initiation and propagation of intermetallics and component layers,which helps to clarify their deformation behavior and fracture forms.The results show that delamination is the early fracture form of laminate with or without intermetallics at Al/Mg interface,so Al/Mg interfacial bonding strength determines the mechanical properties of laminate.Various and irregular intermetallics cracks lead to Al/Mg interface delamination in annealed laminate and help to release stress.Necking and fracture of component layers are observed at the late deformation stage,and the sequence is Al,Mg and Ti layers,resulting from their strength.Angle between crack propagation direction and stretching direction of Mg layer both in rolled and annealed laminates is around 45°due to the effect of shear deformation,and crack convergence leads to final complete fracture of Mg layer.
基金supported by the National Natural Science Foundation of China(No.51505323)the Applied Basic Research Program of Shanxi Province,China(Nos.20210302123117,20210302124658).
基金supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health under Award Numbers R01 AR067306 and R01 AR078241。
文摘Bacterial colonization of orthopedic implants is one of the leading causes of failure and clinical complexities for load-bearing metallic implants. Topical or systemic administration of antibiotics may not offer the most efficient defense against colonization, especially in the case of secondary infection, leading to surgical removal of implants and in some cases even limbs. In this study, laser powder bed fusion was implemented to fabricate Ti3Al2V alloy by a 1:1 weight mixture of CpTi and Ti6Al4V powders. Ti-Tantalum(Ta)–Copper(Cu) alloys were further analyzed by the addition of Ta and Cu into the Ti3Al2V custom alloy. The biological,mechanical, and tribo-biocorrosion properties of Ti3Al2V alloy were evaluated. A 10 wt.% Ta(10Ta) and 3 wt.% Cu(3Cu) were added to the Ti3Al2V alloy to enhance biocompatibility and impart inherent bacterial resistance. Additively manufactured implants were investigated for resistance against Pseudomonas aeruginosa and Staphylococcus aureus strains of bacteria for up to 48 h. A 3 wt.% Cu addition to Ti3Al2V displayed improved antibacterial efficacy, i.e.78%–86% with respect to CpTi. Mechanical properties for Ti3Al2V–10Ta–3Cu alloy were evaluated, demonstrating excellent fatigue resistance, exceptional shear strength, and improved tribological and tribo-biocorrosion characteristics when compared to Ti6Al4V. In vivo studies using a rat distal femur model revealed improved early-stage osseointegration for alloys with10 wt.% Ta addition compared to CpTi and Ti6Al4V. The 3 wt.% Cu-added compositions displayed biocompatibility and no adverse infammatory response in vivo. Our results establish the Ti3Al2V–10Ta–3Cu alloy’s synergistic effect on improving both in vivo biocompatibility and microbial resistance for the next generation of load-bearing metallic implants.
