This study investigated enhancing the wear resistance of Ti6Al4V alloys for medical applications by incorporating Ti C nanoreinforcements using advanced spark plasma sintering(SPS). The addition of up to 2.5wt% Ti C s...This study investigated enhancing the wear resistance of Ti6Al4V alloys for medical applications by incorporating Ti C nanoreinforcements using advanced spark plasma sintering(SPS). The addition of up to 2.5wt% Ti C significantly improved the mechanical properties, including a notable 18.2% increase in hardness(HV 332). Fretting wear tests against 316L stainless steel(SS316L) balls demonstrated a 20wt%–22wt% reduction in wear volume in the Ti6Al4V/Ti C composites compared with the monolithic alloy. Microstructural analysis revealed that Ti C reinforcement controlled the grain orientation and reduced the β-phase content, which contributed to enhanced mechanical properties. The monolithic alloy exhibited a Widmanstätten lamellar microstructure, while increasing the Ti C content modified the wear mechanisms from ploughing and adhesion(0–0.5wt%) to pitting and abrasion(1wt%–2.5wt%). At higher reinforcement levels, the formation of a robust oxide layer through tribo-oxide treatment effectively reduced the wear volume by minimizing the abrasive effects and plastic deformation. This study highlights the potential of SPS-mediated Ti C reinforcement as a transformative approach for improving the performance of Ti6Al4V alloys, paving the way for advanced medical applications.展开更多
Nanoconfinement is a promising approach to simultaneously enhance the thermodynamics,kinetics,and cycling stability of hydrogen storage materials.The introduction of supporting scaffolds usually causes a reduction in ...Nanoconfinement is a promising approach to simultaneously enhance the thermodynamics,kinetics,and cycling stability of hydrogen storage materials.The introduction of supporting scaffolds usually causes a reduction in the total hydrogen storage capacity due to“dead weight.”Here,we synthesize an optimized N-doped porous carbon(rN-pC)without heavy metal as supporting scaffold to confine Mg/MgH_(2) nanoparticles(Mg/MgH_(2)@rN-pC).rN-pC with 60 wt%loading capacity of Mg(denoted as 60 Mg@rN-pC)can adsorb and desorb 0.62 wt%H_(2) on the rN-pC scaffold.The nanoconfined MgH_(2) can be chemically dehydrided at 175℃,providing~3.59 wt%H_(2) with fast kinetics(fully dehydrogenated at 300℃ within 15 min).This study presents the first realization of nanoconfined Mg-based system with adsorption-active scaffolds.Besides,the nanoconfined MgH_(2) formation enthalpy is reduced to~68 kJ mol^(−1) H_(2) from~75 kJ mol^(−1) H_(2) for pure MgH_(2).The composite can be also compressed to nanostructured pellets,with volumetric H_(2) density reaching 33.4 g L^(−1) after 500 MPa compression pressure,which surpasses the 24 g L^(−1) volumetric capacity of 350 bar compressed H_(2).Our approach can be implemented to the design of hybrid H_(2) storage materials with enhanced capacity and desorption rate.展开更多
文摘This study investigated enhancing the wear resistance of Ti6Al4V alloys for medical applications by incorporating Ti C nanoreinforcements using advanced spark plasma sintering(SPS). The addition of up to 2.5wt% Ti C significantly improved the mechanical properties, including a notable 18.2% increase in hardness(HV 332). Fretting wear tests against 316L stainless steel(SS316L) balls demonstrated a 20wt%–22wt% reduction in wear volume in the Ti6Al4V/Ti C composites compared with the monolithic alloy. Microstructural analysis revealed that Ti C reinforcement controlled the grain orientation and reduced the β-phase content, which contributed to enhanced mechanical properties. The monolithic alloy exhibited a Widmanstätten lamellar microstructure, while increasing the Ti C content modified the wear mechanisms from ploughing and adhesion(0–0.5wt%) to pitting and abrasion(1wt%–2.5wt%). At higher reinforcement levels, the formation of a robust oxide layer through tribo-oxide treatment effectively reduced the wear volume by minimizing the abrasive effects and plastic deformation. This study highlights the potential of SPS-mediated Ti C reinforcement as a transformative approach for improving the performance of Ti6Al4V alloys, paving the way for advanced medical applications.
基金supported by the National Key R&D Program of China(2022YFB3803700)National Natural Science Foundation of China(52171186)+1 种基金Young Elite Scientists Sponsorship Program by CAST(2023QNRC001)support from“Zhiyuan Honor Program”for doctoral students,Shanghai Jiao Tong University.
文摘Nanoconfinement is a promising approach to simultaneously enhance the thermodynamics,kinetics,and cycling stability of hydrogen storage materials.The introduction of supporting scaffolds usually causes a reduction in the total hydrogen storage capacity due to“dead weight.”Here,we synthesize an optimized N-doped porous carbon(rN-pC)without heavy metal as supporting scaffold to confine Mg/MgH_(2) nanoparticles(Mg/MgH_(2)@rN-pC).rN-pC with 60 wt%loading capacity of Mg(denoted as 60 Mg@rN-pC)can adsorb and desorb 0.62 wt%H_(2) on the rN-pC scaffold.The nanoconfined MgH_(2) can be chemically dehydrided at 175℃,providing~3.59 wt%H_(2) with fast kinetics(fully dehydrogenated at 300℃ within 15 min).This study presents the first realization of nanoconfined Mg-based system with adsorption-active scaffolds.Besides,the nanoconfined MgH_(2) formation enthalpy is reduced to~68 kJ mol^(−1) H_(2) from~75 kJ mol^(−1) H_(2) for pure MgH_(2).The composite can be also compressed to nanostructured pellets,with volumetric H_(2) density reaching 33.4 g L^(−1) after 500 MPa compression pressure,which surpasses the 24 g L^(−1) volumetric capacity of 350 bar compressed H_(2).Our approach can be implemented to the design of hybrid H_(2) storage materials with enhanced capacity and desorption rate.
