熔体超温处理对GH742返回料凝固组织和力学性能的影响  

Influence of Melt Superheating Treatment on Solidification Microstructure and Mechanical Properties of Ni-Based Superalloy GH742

作　　者：王常帅[1] 吴云胜 张丰之 田强[2] 周兰章[1] Wang Changshuai;Wu Yunsheng;Zhang Fengzhi;Tian Qiang;Zhou Lanzhang(Shi-Changxu Innovation Center for Advanced Materials,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China;High-Temperature Materials Division,Central Iron and Steel Research Institute,Beijing 100081,China)

机构地区：[1]中国科学院金属研究所师昌绪先进材料创新中心,辽宁沈阳110016 [2]钢铁研究总院高温材料研究所,北京100081

出　　处：《稀有金属材料与工程》2022年第11期4270-4278,共9页Rare Metal Materials and Engineering

基　　金：国家科技重大专项(2017-Ⅵ-0018-0090);国家自然科学基金(51971216,51301171);“兴辽英才计划”(XLYC1807038)。

摘　　要：采用熔体超温处理方法考察了熔体超温处理温度对GH742返回料凝固组织和力学性能的影响规律。结果表明:当熔体超温处理温度低于1550℃时,随熔体超温处理温度的升高,晶粒和枝晶组织显著细化,枝晶偏析和合金中N、O、S元素含量降低,然而,温度进一步升高至1600℃,晶粒和枝晶组织粗化、枝晶偏析增大、合金中N、O含量升高。熔体超温处理显著影响枝晶干γ′相特征,却对MC型碳化物影响较小。MC型碳化物形貌为棒状或块状,且随熔体超温处理温度升高无明显变化,但尺寸和面积分数均略微减小。枝晶干γ′相形态则随熔体超温处理升高由近球形向近立方状转变,尺寸呈现先增后减趋势。合适的熔体超温处理可显著提高返回料的室温抗拉伸强度,但对塑性无明显影响,其原因被归因于凝固组织的变化。The melt superheating treatment was carried out for reverted GH742 superalloy.Under the same solidification conditions,the microstructure evolution and its influence on mechanical properties was investigated by changing the melt superheating temperature.The results show that the grain and dendrite are refined,and the dendrite segregation and the contents of N,O and S are decreas ed with the melt superheating temperature increasing from 1450℃ to 1550℃.However,the grain and dendrite becomes coarse,dendrite segregation becomes serious and the contents of N,O increase after the melt superheating treatment at 1600℃.The morphology of MC carbide is rod-shaped or blocky.The melt superheating treatment has no significant influence on the morphology of MC carbide,but slightly decreases its size and area fraction.With increasing melt superheating treatment temperature,γ′morphology changes from near-sphere to cube,butγ′size first reduces with the increase of melt superheating temperature between 1450℃ and 1550℃,but increases when the superheating temperature is higher than 1550℃.Corresponding to this,the tensile strength at room temperature is significantly improved after melt superheating treatment at 1550℃,but the ductile has no obvious change.

关 键 词：熔体超温处理 凝固组织 枝晶偏析 力学性能 GH742 

分 类 号：TG146.15[一般工业技术—材料科学与工程]