材料期刊网

通过微观相场方法研究了Ni₇₅Al₁₅Cr₁₀合金在1073 K时效时, 不同原子间有序能下Cr原子的替代行为. 结果表明, 在γ'有序相中, 同时存在Ni--Al原子反位和Cr原子对Ni和Al原子的替代行为, 其中以替代行为为主; 随着第1,3层Ni--Al和Ni--Cr有序能的增大, Cr原子替代Al位的趋势增大, 替代Ni位的趋势减小; 第2, 4层Ni--Al和Ni--Cr有序能增大时, Cr原子替代Ni位的趋势增大, 替代Al位的趋势减小; 第1, 3层Al--Cr有序能增大时, Cr替代Ni位的趋势增大, 替代Al位的趋势减小; 第2, 4层Al--Cr有序能增大时, Cr替代Ni位的趋势减小, 替代Al位的趋势增大.

The microscopic phase–field model based on long range order (LRO) method was proposed to study Cr substitution behavior in Ni₇₅Al₁₅Cr₁₀ alloy aged at 1073 K. This has been demonstrated by short range order (SRO) methods and experiments such as pseudo–potential, Monte Carlo method and Rutherford back scattering analysis (RBS). Adding ±4 meV to the ordering energy of Ni–Al, Ni–Cr and Al–Cr in 1st—4th nearest–neighborhoods is used to describe the influence of potential field on substitution. On the analysis of atomic images, the order parameters and Cr occupation probabilities, results show that there are coexisted Ni–Al anti–site and Cr substitution for Ni and Al in L12 ordered phase, and Cr substitution occurs much more often than Ni–Al anti–site. As the ordering energies of Ni–Al and Ni–Cr in 1st and 3rd nearest–neighborhoods increase, there is a more increasing tendency of substitution of Cr for Al than for Ni. For the 2nd and 4th nearest–neighborhoods, the
ordering energy makes the tendency of substitution of Cr for Ni increase. Otherwise, with the 1st and 3rd nearest–neighborhoods ordering energies of Al–Cr increasing, the tendency of substitution of Cr increases for Ni but decreases for Al, which is opposite to the cases for the 2nd and 4th nearest–neighborhoods.