论文部分内容阅读
利用相场模型研究了Ni_4Ti_3沉淀相自催化效应的产生机制,基于体系各种能量的变化规律研究了自催化生长效应中合理的Ni_4Ti_3变体群的排列方式.模拟研究结果表明,在模拟最初的时间内,为缓解球形Ni_4Ti_3相与NiTi基体相形态上的不匹配,体系的化学自由能逐渐增大,弹性能和界面能逐渐减小;当Ni_4Ti_3相与NiTi基体相达到最佳匹配后,相变过程中化学自由能逐渐减小,弹性能和界面能逐渐增大;整个相变过程中体系向低能量态发展.同取向变体的梯形排列模式具有最大的优先性,其次是同取向变体的水平排列方式,再次是不同取向变体的边-面排列方式,最不具优先性的是同种变体的垂直排列模式.相场模拟结果深化并拓展了已有实验结论.
The mechanism of the autocatalysis of precipitated Ni_4Ti_3 phase was studied by using the phase field model, and the rational arrangement of Ni_4Ti_3 variants in the autocatalytic growth effect was studied based on the variation of various energies of the system. The simulation results show that, In order to alleviate the phase mismatch between the spherical Ni_4Ti_3 phase and the NiTi phase, the chemical free energy of the Ni_4Ti_3 phase increases and the elastic energy and interfacial energy decrease gradually. When the Ni_4Ti_3 phase and the NiTi phase reach the best match, The chemical free energy decreases, the elastic energy and the interface energy increase gradually, and the system develops to low energy state during the entire phase transformation.The trapezoidal arrangement pattern of the same orientation has the highest priority, followed by the same orientation change The horizontal arrangement of the body is again the edge-face arrangement of the different orientation variants, and the least-preferred is the vertical arrangement of the same variants. The phase field simulation results deepen and extend the existing experimental conclusions.