In the present study, a grade of stainless steel （SS, 410） and copper plates were joined through diffusion bonding by using a nickel interlayer at temperature range of 800-950℃. These were performed through pressin...In the present study, a grade of stainless steel （SS, 410） and copper plates were joined through diffusion bonding by using a nickel interlayer at temperature range of 800-950℃. These were performed through pressing the specimens under a pressure of 12 MPa for 60 min under 1.33×10-2 Pa （10-4 torr） vacuum. The microstructure and phase constitution near the diffusion bonding interface of Cu/Ni and Ni/SS were studied by optical microscopy （OM）, scanning electron microscopy （SEM）, X-ray diffraction （XRD） and an elemental analyses through energy dispersive spectrometry （EDS）. The results indicated that an obvious diffusion zone was formed near both Cu/Ni and Ni/SS interfaces during the vacuum diffusion bonding. The thickness of reaction layer in both interfaces was increased with increasing process temperature. The diffusion transition region near the Cu/Ni and Ni/SS interfaces consist of complete solid solution zone and various phases based on （Fe, Ni）, （Fe, Cr, Ni） and （Fe, Cr）, respectively. From EDS results, three different mixtures of phases were distinguished in SS-Ni interface. The activation energy and rate constant were determined for the growth of these reaction layers and the values become maximum for the （γFe＋Cr＋αFe＋Cr）.phase mixture.展开更多
The Co-based alloy/AISI 410 stainless steel dissimilar welded joint was fabricated by the electron beam welding(EBW)technique.The anomalous microstructure containing the element transition zone(ETZ)and/or core of tail...The Co-based alloy/AISI 410 stainless steel dissimilar welded joint was fabricated by the electron beam welding(EBW)technique.The anomalous microstructure containing the element transition zone(ETZ)and/or core of tail-like zone(CTLZ)is in the weld metal(WM)adjacent to the fusion line.The melting temperature difference between the WM and AISI 410 steel,melt stirring effect and element diffusion can trigger the formation of such anomalous microstructure.In particular,the larger distance of the region in WM away from the fusion line,the smaller CTLZ and larger ETZ occurred.Compared with the fine and ellipsoidal precipitates in the as-welded CTLZ,a large number of chain-type clustered precipitates were detected in the CTLZ and ETZ interface after the aging treatment at 566°C for 1000 h.The element diffusion under elevated temperature in WM is regarded as the crucial factor for such anomalous microstructure evolution during the aging treatment.展开更多
文摘In the present study, a grade of stainless steel （SS, 410） and copper plates were joined through diffusion bonding by using a nickel interlayer at temperature range of 800-950℃. These were performed through pressing the specimens under a pressure of 12 MPa for 60 min under 1.33×10-2 Pa （10-4 torr） vacuum. The microstructure and phase constitution near the diffusion bonding interface of Cu/Ni and Ni/SS were studied by optical microscopy （OM）, scanning electron microscopy （SEM）, X-ray diffraction （XRD） and an elemental analyses through energy dispersive spectrometry （EDS）. The results indicated that an obvious diffusion zone was formed near both Cu/Ni and Ni/SS interfaces during the vacuum diffusion bonding. The thickness of reaction layer in both interfaces was increased with increasing process temperature. The diffusion transition region near the Cu/Ni and Ni/SS interfaces consist of complete solid solution zone and various phases based on （Fe, Ni）, （Fe, Cr, Ni） and （Fe, Cr）, respectively. From EDS results, three different mixtures of phases were distinguished in SS-Ni interface. The activation energy and rate constant were determined for the growth of these reaction layers and the values become maximum for the （γFe＋Cr＋αFe＋Cr）.phase mixture.
基金The authors gratefully acknowledge the National Natural Science Foundation of China(Grant Nos.U1760102 and 52101042).
文摘The Co-based alloy/AISI 410 stainless steel dissimilar welded joint was fabricated by the electron beam welding(EBW)technique.The anomalous microstructure containing the element transition zone(ETZ)and/or core of tail-like zone(CTLZ)is in the weld metal(WM)adjacent to the fusion line.The melting temperature difference between the WM and AISI 410 steel,melt stirring effect and element diffusion can trigger the formation of such anomalous microstructure.In particular,the larger distance of the region in WM away from the fusion line,the smaller CTLZ and larger ETZ occurred.Compared with the fine and ellipsoidal precipitates in the as-welded CTLZ,a large number of chain-type clustered precipitates were detected in the CTLZ and ETZ interface after the aging treatment at 566°C for 1000 h.The element diffusion under elevated temperature in WM is regarded as the crucial factor for such anomalous microstructure evolution during the aging treatment.
