Modeling of Ni4Ti3 precipitation during stress-free and stress-assisted aging of bi-crystalline NiTi shape memory alloys
The phase field method is applied to study the microstructure evolution of Ni4Ti3 precipitates during stress-free and stress-assisted aging of bi-crystalline NiTi shape memory alloys (SAMs)with two different initial Ni-contents of 51.5at.% and 52.5at.% respectively.The simulation results indicate that during stress-free aging of the NiTi alloy with a low supersaturation of Ni (i.e.,Ti-51.5at.%Ni),the Ni4Ti3 precipitates exhibit a heterogeneous distribution with a high number density of particles at the grain boundary,leaving most part the grain interior precipitates free,while for the NiTi alloy with a high supersaturation of Ni (i.e.,Ti-52.5at.%Ni) the Ni4Ti3 precipitates show a homogeneous distribution across the entire simulation system.The stress-assisted aging can give rise to homogeneous distribution of the precipitates,regardless of initial Ni-content,however,the distribution of the variant type within the two grains is heterogeneous.
NiTi SMAs Ni4Ti3 precipitation low-angle grain boundary martensitic transformation phase field simulation
Ke Changbo Cao Shanshan Ma Xiao Zhagn Xinping
School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640,China
国际会议
上海
英文
182-182
2012-10-19（万方平台首次上网日期，不代表论文的发表时间）