溶质含量对快速凝固Co-Cu不混溶合金晶粒细化组织的影响  

Effect of solute content on grain refinement microstructure of rapid solidified Co-Cu immiscible alloy

作　　者：李圣[1] 刘峰[1] 杨根仓[1] 杨伟[2] 

机构地区：[1]西北工业大学凝固技术国家重点实验室,西安710072 [2]南昌航空大学轻合金加工科学与技术国防重点学科实验室,南昌330063

出　　处：《中国有色金属学报》2013年第4期1012-1018,共7页The Chinese Journal of Nonferrous Metals

基　　金：国家重点基础研究发展计划资助项目(2011CB610403);国家杰出青年科学基金资助项目(51125002);凝固技术国家重点实验室开放课题(SKLSP201118)

摘　　要：采用熔融玻璃净化与循环过热相结合手段,研究Co70Cu30和Co50Cu50亚稳不混溶合金的非平衡凝固组织细化规律。结果表明:随着过冷度的增加,不混溶合金的初生枝晶主干不断细化,枝晶碎断现象更加明显。在未发生液相分离条件下,Co50Cu50合金由于具有更高的溶质含量,溶质过冷度增加,动力学过冷度降低,枝晶细化更加明显而易发生碎断。在大过冷度条件下,合金不混溶效应不断增强,液相分离现象发生,凝固组织中分别出现富Co和富Cu区。对于Co70Cu30(ΔT=237 K)和Co50Cu50(ΔT=188 K)合金,溶质含量对快速凝固过程中初生枝晶的影响程度减弱,非平衡凝固组织的晶粒尺寸及成分未发生明显变化。Co50Cu50合金由于具有更低的临界分离过冷度,不混溶阶段经历的时间更长,液相分离进行得更彻底。Adopting molten glass purification combined with cycle superheating method, the effect of solute content on grain refinement regularity of Co70Cu30 and CosoCuso immiscible alloys was investigated under non-equilibrium condition. With the increase of initial undercooling, the trunk of primary dendrite decreases, which generates serious dendrite fragmentation. For samples without liquid separation, the solute undercooling of Co50Cu50 alloy increases because of its higher solute content. Consequently, the kinetics undercooling for growth is suppressed, which leads to refined and broken-up dendrite. With the further increase of undercooling, the immiscible effect is strengthened and liquid separation occurs, which forms Co-rich and Cu-rieh regions. As for Co70Cu30 alloy undereooled by 237 K and Co50Cu5o alloy undercooled by 188 K, the influence of solute content on rapid solidified microstrueture is weakened, which can be inferred from the almost same of the grain size and solute concentration. Moreover, liquid separation proceeds more completely for Co50Cu50 alloy due to the sufficient duration time for immiscible stage arising from the lower critical immiscible undereooling.

关 键 词：不混溶合金 非平衡凝固 晶粒细化 相变动力学 

分 类 号：TG111.4[金属学及工艺—物理冶金] TG146.1[金属学及工艺—金属学]