摘要
采用差示扫描量热仪对DZ22B高温合金凝固过程及相变行为进行描述,对比分析了不同冷速影响下合金二次枝晶间距、碳化物的转变行为。随冷速提高,组织显著细化,二次枝晶间距由冷速5 K/min时125μm持续下降到80 K/min时37μm。枝晶组织的细化可以减弱凝固后期残余液相中溶质偏析,碳化物形貌由连续网状向不连续条块状发生转变。大冷速条件下枝晶间流动管道的变窄及凝固时间的缩短共同抑制Hf元素的趋肤效应,有利于富Hf碳化物相形成。
Solidification process and phase transformation behavior of DZ22 B superalloys were analyzed by differential scanning calorimetry methods. After comparison of solidification microstructure with different cooling rates, the transition regularity of secondary dendrite spacing and carbidesphase were explored. Obvious dendrite refinement occurred with the increase of cooling rate, and the average secondary dendrite spacing decreased from125 μm at the cooling rate of 5 K/min to 37 μm at the cooling rate of 80 K/min. The refinement of dendrite morphology was advantageous for the reduction of solute micro-segregation at later solidification stage, which generated the morphology change of carbides from continuous net shape to dispersive strips or blocks. Moreover,the skin effect of Hf element can be suppressed for higher cooling rate because of the thinner flowing channel and shorter solidification period, which can facilitate the formation of Hf-rich carbides.
作者
刘亚男
杨伟
Liu Yanan;Yang Wei(Engineering Training Center, East China Jiaotong University, Nanchang 330013, China;National Defense Key Discipline Laboratory of Light Alloy Processing Science and Technology, Nanchang Hangkong University, Nanchang 330013, China)
出处
《华东交通大学学报》
2018年第2期99-104,共6页
Journal of East China Jiaotong University
基金
国家自然科学基金项目(51461032)
江西省教育厅资助项目(GJJ14504)
江西省金属材料微结构调控重点实验室开放项目(JW201523005)
关键词
高温合金
冷却速率
组织细化
碳化物
superalloy
cooling rate
microstructure refinement
carbide
作者简介
刘亚男（1982-），女，助理实验师，硕士研究生，研究方向为复合材料。
