LOCAL CHEMISTRY AND THE COHESIVE STRENGTH OF GRAIN BOUNDARIES IN Ni_3Al
LOCAL CHEMISTRY AND THE COHESIVE STRENGTH OF GRAIN BOUNDARIES IN Ni_3Al作者机构:Cornell Univ Ithaca United States
出 版 物:《Acta Metallurgica Sinica(English Letters)》 (金属学报(英文版))
年 卷 期:1995年第8卷第Z1期
页 面:309-318页
核心收录:
学科分类:0810[工学-信息与通信工程] 08[工学] 0805[工学-材料科学与工程(可授工学、理学学位)] 080502[工学-材料学] 0812[工学-计算机科学与技术(可授工学、理学学位)]
主 题:grain boundary chemistry Ni3Al local bonding cohesive strength
摘 要:Local chemistry plays an important role in determining the cohesive strength of grain boundaries in Ni3Al. Doping with B increases the room temperature ductility and changes the fracture mode from intergranular to transgranular, while doping with Zr increases the ductility but leaves the fracture mode predominantly *** Energy Loss Spectroscopy (EELS) and Energy Dispersive X-ray Spectroscopy (EDS) were used to probe the changes in local bonding (and hence the cohesive strength) produced by changes in local chemistry at large angle boundaries in *** addition , small angle tilt boundaries were studied to correlate structure with Nienrichment at the interface. B segregation to Ni-rich grain boundaries was shown to make the bonding similar to that of the bulk, thereby increasing their fracture resistance. Ni-enrichment does not occur in the presence of Zr segregation to grain boundaries. Ni-enrichment to antiphase boundaries (APB) in small angle tilt boundaries lowers the APB energy by reducing the number of high energy Al-Al interactions across the interface. Ni-enrichment to large angle boundaries is expected to produce a similar effect on energy.