Cu/Al bar clad material was fabricated by a drawing process and a subsequent heat treatment.During these processes,intermetallic compounds have been formed at the interface of Cu/Al and have affected its bonding prope...Cu/Al bar clad material was fabricated by a drawing process and a subsequent heat treatment.During these processes,intermetallic compounds have been formed at the interface of Cu/Al and have affected its bonding property.Microstructures of Cu/Al interfaces were observed by OM,SEM and EDX Analyser in order to investigate the bonding properties of the material.According to the microstructure a series of diffusion layers were observed at the interface and the thicknesses of diffusion layers have increased with aging time as a result of the diffusion bonding.The interfaces were composed of 3-ply diffusion layers and their compositions were changed with aging time at 400 °C.These compositional compounds were revealed to be η2,(θ+η2),(α+θ) intermetallic phases.It is evident from V-notch impact tests that the growth of the brittle diffusion layers with the increasing aging time directly influenced delamination distance between the Cu sleeve and the Al core.It is suggested that the proper holding time at 400 °C for aging as post heat treatment of a drawn Cu/Al bar clad material would be within 1 h.展开更多
TaB_(2)-SiC coating modified by different content of MoSi_(2) was fabricated on graphite substrate with SiC inner coating by liquid phase sintering to elevate the anti-oxidation capability of the TaB_(2)-SiC coatings....TaB_(2)-SiC coating modified by different content of MoSi_(2) was fabricated on graphite substrate with SiC inner coating by liquid phase sintering to elevate the anti-oxidation capability of the TaB_(2)-SiC coatings.As compared to the sample with the TaB_(2)-40wt% SiC coating,the coating sample modified with MoSi_(2) exhibited a weight gain trend at lower temperatures,the fastest weight loss rate went down by 76%,and the relative oxygen permeability value reduced from about 1% to near 0.More importantly,the large amount of SiO_(2) glass phase produced over the coating during oxidation was in contact with the modification of MoSi_(2),which was proved to be beneficial to the dispersion of Ta-oxides.A concomitantly formed continuous Ta-Si-O-B compound glass layer showed excellent capacity to prevent oxygen penetration.However,when the TaB_(2) content was sacrificed to increase the MoSi_(2) content,the relative oxygen permeability of the coating increased instead of decreased.Thus,on the basis of ample TaB_(2) content,increasing the MoSi_(2) content of the coating is conducive to reducing the relative oxygen permeability of the coatings in a broad temperature region.展开更多
基金Project supported by the Fundamental Materials Development funded by the Korean Ministry of Knowledge Economy
文摘Cu/Al bar clad material was fabricated by a drawing process and a subsequent heat treatment.During these processes,intermetallic compounds have been formed at the interface of Cu/Al and have affected its bonding property.Microstructures of Cu/Al interfaces were observed by OM,SEM and EDX Analyser in order to investigate the bonding properties of the material.According to the microstructure a series of diffusion layers were observed at the interface and the thicknesses of diffusion layers have increased with aging time as a result of the diffusion bonding.The interfaces were composed of 3-ply diffusion layers and their compositions were changed with aging time at 400 °C.These compositional compounds were revealed to be η2,(θ+η2),(α+θ) intermetallic phases.It is evident from V-notch impact tests that the growth of the brittle diffusion layers with the increasing aging time directly influenced delamination distance between the Cu sleeve and the Al core.It is suggested that the proper holding time at 400 °C for aging as post heat treatment of a drawn Cu/Al bar clad material would be within 1 h.
基金supported by the Fundamental Research Funds for the Central Universities(No.2018GF14).
文摘TaB_(2)-SiC coating modified by different content of MoSi_(2) was fabricated on graphite substrate with SiC inner coating by liquid phase sintering to elevate the anti-oxidation capability of the TaB_(2)-SiC coatings.As compared to the sample with the TaB_(2)-40wt% SiC coating,the coating sample modified with MoSi_(2) exhibited a weight gain trend at lower temperatures,the fastest weight loss rate went down by 76%,and the relative oxygen permeability value reduced from about 1% to near 0.More importantly,the large amount of SiO_(2) glass phase produced over the coating during oxidation was in contact with the modification of MoSi_(2),which was proved to be beneficial to the dispersion of Ta-oxides.A concomitantly formed continuous Ta-Si-O-B compound glass layer showed excellent capacity to prevent oxygen penetration.However,when the TaB_(2) content was sacrificed to increase the MoSi_(2) content,the relative oxygen permeability of the coating increased instead of decreased.Thus,on the basis of ample TaB_(2) content,increasing the MoSi_(2) content of the coating is conducive to reducing the relative oxygen permeability of the coatings in a broad temperature region.
