论文部分内容阅读
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Ni75Al7.5V17.5合金于1 273 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.
In order to reveal the mechanism of the formation of new phase in the initial phase of alloy solid phase transformation, especially the formation mechanism of D022 phase transition twinning, the three-phase micro-phase field model was used to simulate the first three stages of the precipitation process of Ni75Al7.5V17.5 alloy at 1 273 K The results show that the Ni3Al ordered phase of L12 structure firstly co-lattice nucleus from the parent phase along the inertial plane (100), and then the Ni3V ordered phase of D022 structure precipitates the phase of L12 phase and parent phase Because of the large coherent mismatch formed on the inverting domains of {100}, resulting in high energy and instability, the antiphase boundaries are destroyed in the two-phase growth, whereas the {110} (100), the three variants of D022 are arranged orthogonally to each other to form a stepped {110} twin plane.