The deposition process of the Ni75 Al7.5 V17.5 alloy is simulated by the microscopic phase field method. At first, the ordered L12 phase Ni3Al nucleates along the habit (100) plane of the matrix, and then the D022 structured Ni3 V ordered phase nucleates along the interface between the matrix and the L12 phase. The microscopic phase⁃field simulation implicates that the anti⁃phase boundary ( APB ) along {100} would be destroyed during growth of the two phases due to the higher interface energy which is formed by large coherent misfit of the interface{100}. The interface energy of the crystal plane{110}is lower than that of the APB, and the step⁃like structured twin plane{110}is formed because of being normally arranged of the three variants of the D022 phase.%为揭示合金固态相变初期新相形成机制，尤其是D022相变孪晶形成机制，利用三元微观相场模型对Ni75 Al7．5 V17．5合金于1273 K 下等温时效沉淀过程的前3个阶段进行了模拟．计算结果表明，L12结构的Ni3Al有序相首先沿惯析面（100）从母相中共格形核，而后D022结构的Ni3V有序相在先析出的L12相和母相的相界形核．由于{100}的反相畴界上形成较大的共格失配，导致能量较高且不稳定，反相畴界在两相生长中遭到破坏，而晶面{110}的界面能比{100}的反相畴界能低，生长过程中D022的3种变体互相正交排列形成阶梯状结构的{110}孪晶面．
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