This study reports the investigations for repair of thermoplastic based automotive bumpers and bars with modified friction stir welding(MFSW)process.For MFSW,consumable tool of polyamide6(PA6)composite has been used f...This study reports the investigations for repair of thermoplastic based automotive bumpers and bars with modified friction stir welding(MFSW)process.For MFSW,consumable tool of polyamide6(PA6)composite has been used for joining of acrylonitrile butadiene styrene(ABS)composites.The dissimilar thermoplastics were processed for maintaining a useful range of melt flow properties followed by preparation of feed stock filament for fused deposition modeling(FDM)process through screw extrusion.Finally,3D printed PA6 based consumable rapid tool(RT)was prepared for MFSW.The joints prepared were subjected to flexural,hardness,morphological and thermal testing.The study has suggested the that maximum mechanical strength was obtained for sample welded at 1400 r/min,50 mm/min transverse speed and 3 mm plunge depth,whereas the minimum mechanical strength was obtained for sample welded at 1000 r/min,30 mm/min transverse speed and 2 mm plunge depth.The results are also supported with thermal analysis and photomicrographs.展开更多
Ti-47Al-2Nb-2Cr-0.15B(mole fraction,%)alloy was vacuum brazed with amorphous and crystalline Ti.25Zr-12.5Cu-12.5Ni-3.0Co-2.0Mo(mass fraction,%)filler alloys,and the melting,spreading and gap filling behaviors of the a...Ti-47Al-2Nb-2Cr-0.15B(mole fraction,%)alloy was vacuum brazed with amorphous and crystalline Ti.25Zr-12.5Cu-12.5Ni-3.0Co-2.0Mo(mass fraction,%)filler alloys,and the melting,spreading and gap filling behaviors of the amorphous and crystalline filler alloys as well as the joints brazed with them were investigated in details.Results showed that the amorphous filler alloy possessed narrower melting temperature interval,lower liquidus temperature and melting active energy compared with the crystalline filler alloy,and it also exhibited better brazeability on the surface of the Ti.47Al.2Nb.2Cr.0.15B alloy.The TiAl joints brazed with crystalline and amorphous filler alloys were composed of two interfacial reaction layers and a central brazed layer.Under the same conditions,the tensile strength of the joint brazed with the amorphous filler alloy was always higher than that with the crystalline filler alloy.The maxmium tensile strength of the joint brazed at 1273 K with the amorphous filler alloy reached 254 MPa.展开更多
A 9% Cr ferritic steel weld metal containing 1% Co, partially substituted for nickel, was prepared by submerged arc welding (SAW) processing. The microstructure and creep properties of the weld metal were investigated...A 9% Cr ferritic steel weld metal containing 1% Co, partially substituted for nickel, was prepared by submerged arc welding (SAW) processing. The microstructure and creep properties of the weld metal were investigated. The microstructure exhibited a fully tempered martensitic structure free of δ-ferrite. The creep properties of the obtained weld metal were inferior to those of the P92 base metal at 600 and 650 °C. The values of A and n for weld metal in the Norton power law constitution at 650 °C are 1.1×10?21 and 8.1, respectively.展开更多
文摘This study reports the investigations for repair of thermoplastic based automotive bumpers and bars with modified friction stir welding(MFSW)process.For MFSW,consumable tool of polyamide6(PA6)composite has been used for joining of acrylonitrile butadiene styrene(ABS)composites.The dissimilar thermoplastics were processed for maintaining a useful range of melt flow properties followed by preparation of feed stock filament for fused deposition modeling(FDM)process through screw extrusion.Finally,3D printed PA6 based consumable rapid tool(RT)was prepared for MFSW.The joints prepared were subjected to flexural,hardness,morphological and thermal testing.The study has suggested the that maximum mechanical strength was obtained for sample welded at 1400 r/min,50 mm/min transverse speed and 3 mm plunge depth,whereas the minimum mechanical strength was obtained for sample welded at 1000 r/min,30 mm/min transverse speed and 2 mm plunge depth.The results are also supported with thermal analysis and photomicrographs.
基金Foundation item:Project(51865012)supported by the National Natural Science Foundation of ChinaProject(2016005)supported by the Open Foundation of National Engineering Research Center of Near-net-shape Forming for Metallic Materials,China+2 种基金Project(GJJ170372)supported by the Science Foundation of Educational Department of Jiangxi Province,ChinaProject(JCKY2016603C003)supported by the GF Basic Research Project,ChinaProject(JPPT125GH038)supported by the Research Project of Special Furnishment and Part,China
文摘Ti-47Al-2Nb-2Cr-0.15B(mole fraction,%)alloy was vacuum brazed with amorphous and crystalline Ti.25Zr-12.5Cu-12.5Ni-3.0Co-2.0Mo(mass fraction,%)filler alloys,and the melting,spreading and gap filling behaviors of the amorphous and crystalline filler alloys as well as the joints brazed with them were investigated in details.Results showed that the amorphous filler alloy possessed narrower melting temperature interval,lower liquidus temperature and melting active energy compared with the crystalline filler alloy,and it also exhibited better brazeability on the surface of the Ti.47Al.2Nb.2Cr.0.15B alloy.The TiAl joints brazed with crystalline and amorphous filler alloys were composed of two interfacial reaction layers and a central brazed layer.Under the same conditions,the tensile strength of the joint brazed with the amorphous filler alloy was always higher than that with the crystalline filler alloy.The maxmium tensile strength of the joint brazed at 1273 K with the amorphous filler alloy reached 254 MPa.
基金Project (No 51074113) supported by the National Natural ScienceFoundation of China
文摘A 9% Cr ferritic steel weld metal containing 1% Co, partially substituted for nickel, was prepared by submerged arc welding (SAW) processing. The microstructure and creep properties of the weld metal were investigated. The microstructure exhibited a fully tempered martensitic structure free of δ-ferrite. The creep properties of the obtained weld metal were inferior to those of the P92 base metal at 600 and 650 °C. The values of A and n for weld metal in the Norton power law constitution at 650 °C are 1.1×10?21 and 8.1, respectively.
