时效温度对Ni-Al-V合金筏化影响的微观相场模拟

摘要

基于微观相场动力学模型,以Ni<,75>Al<,25-x>V<,x>合金为对象,研究时效温度变化对沉淀相竞争生长机制及筏状组织形成的影响.结果表明:相的生长和粗化存在各向异性和竞争机制;当具有生长各相异性的DO<,22>相数量较少、尺寸较大时,易形成单一方向排布的组织,从而促使具有生长各向同性的L12相也沿着特定的方向生长,最终形成具有高度择向生长的"筏状"组织,且随着时效温度的降低,沉淀相提前析出;若L12相先析出,时效温度越低,DO<,22>相越多,组织筏化越不明显;若DO<,22>先析出,时效温度越低,DO<,22>相越少,组织筏状越显著.%Based on the microscopic phase-field kinetic model and Ni75Al25-xVx alloy, the influences of ageing temperature on the competitive growth mechanism and raft structure were studied. The results show that the growth and coarsening of phase is a competitive process. It will form raft structure when the number of DO22 is less and the size is larger, causing Ll2 phase growing along the same direction. The precipitate phases appear earlier at a low temperature.There is more DO22 grain and not obvious raft structure at lower temperature if L12 phase precipitates first. There is less DO22 grain and obvious raft structure at lower temperature ifDO22 phase precipitates first.