相场法研究弹性畸变能对Ni-Al合金有序化过程的影响

Study on the Effect of Elastic Strain Energy on the Ordering Process of Ni-Al Alloy by Phase-Field

采用微观弹性相场动力学模型,研究由共格错配产生的弹性畸变能对Ni-Al合金沉淀过程中γ′(Ni3Al)相有序化过程的影响。模拟结果表明,对于不同的沉淀机制,如非经典形核、非经典形核与失稳分解的混合机制及失稳有序化,弹性畸变能均阻碍Al原子在β格点的占位,从而阻碍有序化过程的进行。同一时间步长下,考虑弹性畸变能的合金,其γ′相内浓度和长程序参数曲线的高度和宽度均小于忽略弹性畸变能的合金,曲线分布更加弥散。弹性畸变能改变了γ′相的空间排列及微观形貌,最终形成沿弹性'软方向'择优排列的共格微观组织。

Using the phase-field microelasticity model, we studied the effect of elastic strain energy （ESE） resulted from the precipitation misfit on the ordering process of y＇ （Ni3Al） phase. The simulation results show that ESE always presents impediment effect for different precipitation mechanisms, such as non-classical nucleation, the mixed style of non-classical nucleation and spinodal decomposition, spinodal ordering; and slows down the occupation probability （OP） of A1 atom at fl site, and impedes the ordering process. At the same time step, the height and the width of the concentration and long-range order parameter （LROP） are small in the system involving ESE.ESE changes the spatial arrangement and microstructure, and leads to the preferred orientation