相场法研究Ni-Al间作用势对Ni75Al14Cr11合金L10预析出相的影响

采用微观相场法研究了Ni_(75)Al_(14)Cr_(11)合金第1个近邻到第4个近邻Ni-Al原子间相互作用势对L1_0预析出相沉淀过程的影响。结果表明,当第3近邻Ni-Al原子间相互作用势增大或第4种近邻Ni-Al原子间相互作用势减少时,L1_0预析出相和L1_2平衡相均提前沉淀,且L1_0预析出相体积分数减少而L1_2相的最终体积分数几乎不变;当第3近邻Ni-Al原子间相互作用势减少或第4近邻Ni-Al原子间相互作用势的增大时,L1_0预析出相和L1_2最终相都会推迟沉淀,且L1_0预析出相和L1_2相体积分数均增大;与上述2种情况相比,改变第1近邻Ni-Al原子间相互作用势对L1_0预析出相沉淀过程的影响较小,而改变第2近邻Ni-Al原子间相互作用势对沉淀过程几乎没有影响。进一步研究表明,Ni-Al原子间相互作用势改变不影响合金的沉淀机制,将影响L1_0预析出相、L1_2平衡相的析出时间、速度和2种相的体积分数,沉淀形貌等,从而影响Ni_(75)Al_(14)Cr_(11)高温合金的结构和性能,对合金优化设计有指导意义。

Phase-field simulation for influence of Ni-Al interatomic potential on L10 pre-precipitation phase of Ni75Al14Cr11 alloy

The influence of Ni-Al interatomic potential from the first-nearest neighbor to the fourth-nearest neighbor on the precipitation process of L1₀ pre-precipitation phase in Ni₇₅Al₁₄Cr₁₁ alloy was investigated by the Microscopic Phase-Field method. As the third-nearest Ni-Al interatomic potential increases or the fourth-nearest interatomic potential decreases, L1₀ pre-precipitation phase and L1₂ phase appears in advance; besides, the volume fraction of L1₀ pre-precipitated phase decreases while the final volume fraction of L1₂ phase almost remains unchanged. Whereas the opposite, L1₀ pre-precipitation phase and L1₂ phase appears later; besides, the volume fraction of both phases increases. Compared with the above two, the first-nearest interatomic potential has the less impact and the second-nearest Ni-Al interatomic potential has the least impact on the precipitation process of L1₀ pre-precipitation phase and L1₂ phase. Further research shows that Ni-Al interatomic potential does not affect the precipitation mechanism of the alloy and will affect the precipitation time, speed, volume fraction and precipitation morphology of L1₀ pre-precipitation phase and L1₂ equilibrium phase, thus affecting the structure and properties of Ni₇₅Al₁₄Cr₁₁ superalloy, which has guiding significance for alloy optimization design.