合金成分对定向凝固柱晶高温合金热裂倾向性的影响  

Effects of Chemical Compositions on Hot Tearing of Directionally Solidified Alloys

作　　者：王艳丽[1] 黄朝晖[1] 张强[1] 谭永宁[1] 张宏炜[1] 贾新云[1] 赵希宏[1] 李嘉荣[1] 

机构地区：[1]北京航空材料研究院先进高温结构材料国防科技重点实验室,北京100095

出　　处：《材料工程》2009年第6期35-38,共4页Journal of Materials Engineering

摘　　要：为研究定向凝固柱晶高温合金薄壁铸件凝固过程的热裂纹形成倾向,采用定向凝固空心薄壁管状试样,考察了Ti,Zr,Hf,Al和B等元素对定向凝固柱晶高温合金热裂倾向性的影响;采用SEM、断口分析及DSC方法,分析了热裂的晶界宏观形态。结果表明:随着Ti含量的增加,γ/γ′共晶增多,尺寸增大,合金凝固温度范围变大,定向合金的热裂倾向性严重;Zr元素含量增加,促成共晶形成,合金出现热裂纹;Hf含量的变化对合金的热裂没有影响;Al,B含量增加,微观组织无明显变化,但合金凝固温度范围变大,导致定向凝固合金出现热裂。Effects of the elements, such as Ti, Zr, Hf, AI and B on hot tearing susceptibility during directional solidification were investigated by tube-like directional samples with thickness of 1.0 mm in walls. The results of SEM, DSC and fracture analysis of the elements on the solidification of the alloys were presented. It is found that titanium promotes the formation ofγ/γ′ eutectic, increases its sizes, moreover changes the solidified temperature range of alloys, which leads to crack formation and poor castability. Increasing Zr content promotes eutectic and enlarges hot tearing. During directional solidification changing Hf content can hardly result in the hot tearing of alloys. Increasing Al or B content shows only a little microstructural evolution but enlarges the solidified temperature ranges of alloys, thus alloys with a strong tendency to hot tearing.

关 键 词：定向凝固 高温合金 热裂 

分 类 号：TG132.32[一般工业技术—材料科学与工程]