PRECIPITATION HARDENING IN B2-ORDERED NiAl BY Ni_(2)AlTi COMPOUND  

作　　者：W.H. Tian, K. Ohishi and M. Nemoto 1)Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083, China 2)Department of Materials Science and Engineering, Faculty of Engineering 36, Kyushu University, Fuk 

出　　处：《Acta Metallurgica Sinica(English Letters)》2001年第5期313-318,共6页金属学报（英文版）

基　　金：supported by the grant-in-aid for Scientific Research from the Ministry of Education,Science and Culture of Japan;Financial support of the National Natural Science Foundation of China(Grant No.59971008)is also acknowledged.

摘　　要：Microstructural variations and correlated hardness changes in B2-ordered NiAl containing fine precipitation of Ni2AlTi have been investigated by means of transmission electron microscopy (TEM) and hardness tests. The amount of age hardening is not large as compared to the large microstructural variations during aging. TEM observations have revealed that the L21-type Ni2AlTi precipitates keep a lattice coherency with the NiAl matrix at the beginning of aging. By longer periods of aging Ni2AlTi precipitates lose their coherency and change their morphology to the globular ones surrounded by misfit dislocations. The temperature dependence of the yield strength of precipitate-containing B2-ordered NiAl was investigated by compression tests over the temperature range of 873-1273 K. The fine precipitation of Ni2AlTi was found to enhance greatly the yield strength and the high-temperature strength is comparable with that of superalloy Mar-M200.Microstructural variations and correlated hardness changes in B2-ordered NiAl containing fine precipitation of Ni2AlTi have been investigated by means of transmission electron microscopy (TEM) and hardness tests. The amount of age hardening is not large as compared to the large microstructural variations during aging. TEM observations have revealed that the L21-type Ni2AlTi precipitates keep a lattice coherency with the NiAl matrix at the beginning of aging. By longer periods of aging Ni2AlTi precipitates lose their coherency and change their morphology to the globular ones surrounded by misfit dislocations. The temperature dependence of the yield strength of precipitate-containing B2-ordered NiAl was investigated by compression tests over the temperature range of 873-1273 K. The fine precipitation of Ni2AlTi was found to enhance greatly the yield strength and the high-temperature strength is comparable with that of superalloy Mar-M200.

关 键 词：ALUMINUM HARDENING Mechanical properties NICKEL Precipitation (chemical) 

分 类 号：TG146[一般工业技术—材料科学与工程]