热稳定处理时间对TNM合金糊状区组织的影响  

Effect of Thermal Stabilization Time on Microstructure of Mushy Zone of TNM Alloy

作　　者：李志平 骆良顺[1] 孙雄凯 杨慧敏 刘桐[1] 王亮[1] 张东徽 苏彦庆[1] 郭景杰[1] 傅恒志[1] Li Zhiping;Luo Liangshun;Sun Xiongkai;Yang Huimin;Liu Tong;Wang Liang;Zhang Donghui;Su Yanqing;Guo Jingjie;Fu Hengzhi(National Key Laboratory for Precision Hot Processing of Metals,Harbin Institute of Technology,Harbin 150001,China;School of Materials Science and Engineering,Heilongjiang Institute of Technology,Harbin 150001,China)

机构地区：[1]哈尔滨工业大学金属精密热加工国家级重点实验室,黑龙江哈尔滨150001 [2]黑龙江工程学院材料与化学工程学院,黑龙江哈尔滨150001

出　　处：《稀有金属材料与工程》2020年第11期3938-3942,共5页Rare Metal Materials and Engineering

基　　金：国家重点研发计划项目(2016YFB0301201);国家自然科学基金项目(51671073);云南省重大科技专项计划(2018ZE002);云南稀贵金属材料基因工程一期项目(2018ZE013)。

摘　　要：利用真空非自耗电弧炉制备了TNM(Ti-44Al-4Nb-1Mo-0.1B,原子分数,%)合金锭,研究其铸态组织形貌,并利用Bridgeman定向凝固装置对TNM合金进行热稳定处理实验,分析热稳定处理时间对合金定向凝固糊状区的影响。结果显示,其铸态组织是以(α2+γ)片层团为主体,网络状B2相、细小的γ相及硼化物分布于片层团间的近片层组织。热稳定处理时,热稳定时间越长、TNM合金固/液界面越平整,界面前沿温度场和溶质场趋向均匀,但从减少坩埚对熔体污染的角度考虑,热稳定处理时间不宜过长,30~60 min的热稳定时间即可提供平整的定向凝固启动界面。热稳定处理影响着TNM合金固/液界面附近固液两相中Al元素的分布,进而影响硼化物的分布。The ingots of TNM alloy(Ti-44Al-4Nb-1Mo-0.1B,at%)were obtained by a non-consumable electric arc melting furnace.As-cast microstructure of TNM alloy was investigated.Liquid metal cooling Bridgman-type apparatus was employed in the heat stabilization experiment of TNM alloy and the effect of thermal stabilization time on the mushy zone of TNM alloy during directional solidification was investigated.The results show the as-cast microstructure of TNM alloy consists of a major of(α2+γ)lamellar colonies,network-like B2 phase,smallγphase and boride at the interface of colonies.With the thermal stabilization time increasing,the solid/liquid interface comes to a planar one and the field of temperature and solute in the melt in front of solid/liquid interface become s more homogenous in thermal stabilization test.However,overmuch thermal stabilization time will make the melt contaminated by the crucible.The study shows the thermal stabilization time of 30~60 min is sufficient to provide a planar starting interface for directional solidific ation.Thermal stabilization affects the distribution of Al in solid and liquid phases near the solid/liquid interface of TNM alloy,and further affects the distribution of borides.

关 键 词：TNM合金 热稳定处理 糊状区 显微组织 组织演化 

分 类 号：TG146.23[一般工业技术—材料科学与工程]