CBr_4-C_2Cl_6共晶合金生长的三维多相场模拟 Ⅱ.层片间距对形态演化的影响  

THREE DIMENSIONAL MULTI-PHASE FIELD SIMULATION OF GROWTH OF EUTECTIC CBr_4-C_2Cl_6 ALLOY Ⅱ.Effect of Lamellar Spacing on Morphology Evolution

作　　者：杨玉娟[1] 严彪[1] 

机构地区：[1]同济大学材料科学与工程学院上海市金属功能材料开发应用重点实验室,上海200092

出　　处：《金属学报》2010年第7期787-793,共7页Acta Metallurgica Sinica

基　　金：中国博士后科学基金项目20090460654;上海市科委项目0752nm004和08IDZ2201300资助~~

摘　　要：利用KKSO三维多相场模型,在等层片宽度和厚度条件下,研究了CBr_4-C_2Cl_6共晶合金在不同初始层片间距条件下的三维形态演化过程、层-棒转变及三维层片间距调整机制,研究表明,对于亚共晶、共晶成分的CBr_4-C_2Cl_6合金,不同的初始层片间距可能导致共晶形态发生层-棒转变,且发生层-棒转变的趋势与初始层片间距的大小有关;而过共晶成分的CBr_4-C_2Cl_6合金不会发生层-棒转变,维持层片生长.而且当无量纲初始层片间距在0.598—2.336之间变化时,随着层片间距的增加,其演化顺序为:层片湮没后形成1λO→T-xλO→1λO→2λO→分叉与形核→Z字型分叉→无序组织.研究还表明,三维层片间距调整机制与二维层片间距调整机制类似,基本机制为层片湮没和层片分叉.当初始层片间距较小时,发生层片湮没现象.而当初始层片间距较大时,层片发生分叉.但由于多了第三方向的限制作用,三维层片间距调整机制比二维复杂.Using KKSO multi-phase field model,with equal lamellar width and thickness,three dimensional（3D）morphology evolution,lamellar-rod transition and the mechanism of adjustment of lamellar spacing of CBr_4-C_2Cl_6 alloys are investigated at different initial lamellar spacings.It＇s found that,as for the hypoeutectic and eutectic CBr_4-C_2Cl_6 alloy,different initial lamellar spacings may lead to lamellar-rod transition,which is related to the initial lamellar spacings.The CBr_4-C_2Cl_6 hypereutectic lamellar alloy can＇t transit to rod-like eutectic,with the increase of the dimensionless initial lamellar spacings∧in the range of 0.598—2.336,the sequence of morphology evolution is： lamellar merges to form 1λO→T-xλO→1λO→2λO→lamellar branching→zigzag bifurcation→lamellar destabilizes to form the disordered pattern.The simulated results also showed that the mechanism of adjustment of lamellar spacing in 3D of the CBr_4-C_2Cl_6 hypereutectic alloy is similar to that in two dimensions（2D）,which is lamellar annihilation and branching on the whole,the lamellar annihilation takes place with a smaller initial lamellar spacing while the lamellar branching takes place with a bigger initial lamellar spacing.The adjustment mechanism of the lamellar spacing in 3D is more complex than that in 2D because of the additional effect of the third dimension.

关 键 词：三维多相场 共晶 形态演化 层-棒转变 层片间距调整 

分 类 号：TG111.5[金属学及工艺—物理冶金]