【摘要】 采用双模晶体相场法研究六方相向正方相的转变。分别针对倾侧角为0°、15°、30°和45°,晶粒取向差为6°的六方相体系做了研究。结果表明:六方晶粒长大、溶合、并形成共格晶界,位错组沿六方晶界均匀分布,并有2种取向。正方相在位错组处形核,并且其取向取决于位错组取向。每一种倾侧角的体系中均形成2个取向正方相的变体。针对倾侧角为0°、15°、30°和45°的六方相体系,生成的四方相相变体之间的取向差分别为30°、30°、10°和5°。不同取向的正方相晶粒长大熟化的方式有差异,位于有利取向的晶粒将会优先生长并占据主导地位。以共格晶界形式长大的晶粒,晶界处有位错组生成以松弛晶粒长大的应力集中。更多还原

【Abstract】 A two-mode phase field crystal(PFC) method was employed to focus on hexagonal to square phase transformation. Hexagonal phase with a misorientation of 6° and a tilt angle of 0°, 15°, 30°, and 45° were investigated. Results show that the hexagonal grains grow up, coalesce and form coherent grain boundaries with dislocation sets in two orientations. Square phases nucleate on these dislocation sets and their orientations are determined by dislocation sets. These square grains have two variants at each tilt angle, and the misorientations are 30°, 30°, 10°, and 5° when tilt angles are 0°, 15°, 30°, and 45°, respectively. Square grains with different orientations grow and ripen in different paces, and the grains located in preferential orientation will dominate. Dislocation sets are generated to relieve strain concentration that rises from grain growth in coherent boundaries.更多还原