The high entropy alloys(HEAs)are the newly developed high-performance materials that have gained significant importance in defence,nuclear and aerospace sector due to their superior mechanical properties,heat resistan...The high entropy alloys(HEAs)are the newly developed high-performance materials that have gained significant importance in defence,nuclear and aerospace sector due to their superior mechanical properties,heat resistance,high temperature strength and corrosion resistance.These alloys are manufactured by the equal mixing or larger proportions of five or more alloying elements.HEAs exhibit superior mechanical performance compared to traditional engineering alloys because of the extensive alloying composition and higher entropy of mixing.Solid state welding(SSW)techniques such as friction stir welding(FSW),rotary friction welding(RFW),diffusion bonding(DB)and explosive welding(EW)have been efficiently deployed for improving the microstructural integrity and mechanical properties of welded HEA joints.The HEA interlayers revealed greater potential in supressing the formation of deleterious intermetallic phases and maximizing the mechanical properties of HEAs joints.The similar and dissimilar joining of HEAs has been manifested to be viable for HEA systems which further expands their industrial applications.Thus,the main objective of this review paper is to present a critical review of current state of research,challenges and opportunities and main directions in SSW of HEAs mainly CoCrFeNiMn and Al_xCoCrFeNi alloys.The state of the art of problems,progress and future outlook in SSW of HEAs are critically reviewed by considering the formation of phases,microstructural evolution and mechanical properties of HEAs joints.展开更多
With the trends of miniaturization and high density of electronic packaging,there has been an urgent demand to open up lead-free solders with high strength and ductility.In this study,a ZrO_(2)-reinforced Sn1.0Ag0.5Cu...With the trends of miniaturization and high density of electronic packaging,there has been an urgent demand to open up lead-free solders with high strength and ductility.In this study,a ZrO_(2)-reinforced Sn1.0Ag0.5Cu composite solder was designed.First,surface modification on ZrO_(2) was conducted with ball milling-pyrolysis method.Subsequently,NiO modified ZrO_(2)(NiO/ZrO_(2))was added to the solder matrix with ultrasonic stirring.The morphology and interface of NiO/ZrO_(2) were discussed.Moreover,the microstructure,interface and mechanical properties of the composite solders were systematically studied.The results showed that NiO nanoparticles were evenly adhered to the ZrO_(2) surface,and the interface relationship between them was semi-coherent and coherent.Further,an appropriate addition of NiO/ZrO_(2) could refine the microstructure of composite solders.The refinement mechanism was systematically investigated.Besides,a micro-mechanical lock and non-micropored clean interface was formed between NiO/ZrO_(2) and the solder matrix.The Sn/NiO/ZrO_(2) interface system based on mutual solid solution was ingeniously designed.The ultimate tensile strength and elongation were increased synergistically,and the fracture mechanism transformed from a ductile−brittle mixed fracture mode to a ductile fracture mode.Therefore,a lead-free solder with high strength and ductility was obtained.展开更多
基金financially supported by Ministry of Science and Higher Education of the Russian Federation(Grant No.FENU-2023-0013)。
文摘The high entropy alloys(HEAs)are the newly developed high-performance materials that have gained significant importance in defence,nuclear and aerospace sector due to their superior mechanical properties,heat resistance,high temperature strength and corrosion resistance.These alloys are manufactured by the equal mixing or larger proportions of five or more alloying elements.HEAs exhibit superior mechanical performance compared to traditional engineering alloys because of the extensive alloying composition and higher entropy of mixing.Solid state welding(SSW)techniques such as friction stir welding(FSW),rotary friction welding(RFW),diffusion bonding(DB)and explosive welding(EW)have been efficiently deployed for improving the microstructural integrity and mechanical properties of welded HEA joints.The HEA interlayers revealed greater potential in supressing the formation of deleterious intermetallic phases and maximizing the mechanical properties of HEAs joints.The similar and dissimilar joining of HEAs has been manifested to be viable for HEA systems which further expands their industrial applications.Thus,the main objective of this review paper is to present a critical review of current state of research,challenges and opportunities and main directions in SSW of HEAs mainly CoCrFeNiMn and Al_xCoCrFeNi alloys.The state of the art of problems,progress and future outlook in SSW of HEAs are critically reviewed by considering the formation of phases,microstructural evolution and mechanical properties of HEAs joints.
基金supported by the China Scholarship Council(No.202008050209)。
文摘With the trends of miniaturization and high density of electronic packaging,there has been an urgent demand to open up lead-free solders with high strength and ductility.In this study,a ZrO_(2)-reinforced Sn1.0Ag0.5Cu composite solder was designed.First,surface modification on ZrO_(2) was conducted with ball milling-pyrolysis method.Subsequently,NiO modified ZrO_(2)(NiO/ZrO_(2))was added to the solder matrix with ultrasonic stirring.The morphology and interface of NiO/ZrO_(2) were discussed.Moreover,the microstructure,interface and mechanical properties of the composite solders were systematically studied.The results showed that NiO nanoparticles were evenly adhered to the ZrO_(2) surface,and the interface relationship between them was semi-coherent and coherent.Further,an appropriate addition of NiO/ZrO_(2) could refine the microstructure of composite solders.The refinement mechanism was systematically investigated.Besides,a micro-mechanical lock and non-micropored clean interface was formed between NiO/ZrO_(2) and the solder matrix.The Sn/NiO/ZrO_(2) interface system based on mutual solid solution was ingeniously designed.The ultimate tensile strength and elongation were increased synergistically,and the fracture mechanism transformed from a ductile−brittle mixed fracture mode to a ductile fracture mode.Therefore,a lead-free solder with high strength and ductility was obtained.
