热处理对定向凝固CMSX-6合金组织及拉伸性能的影响.doc

热处理对定向凝固CMSX-6合金组织及拉伸性能的影响 贾志宏，朱翔，马铭泽，徐亮，王顺成，赵玉涛 （江苏大学 材料科学与工程学院，江苏镇江 212013） 摘要：采用高速凝固法制备了CMSX-6镍基高温合金定向凝固试样。研究了热处理前后不同部位的显微组织和拉伸性能。结果表明，铸态试样先凝固部分比后凝固部分的枝晶组织更为细密，一次枝晶间距较小，共晶组织含量较少，而抗拉强度高，延伸率较小。热处理后初生相充分固溶形成了成分均一的组织，γ′相得到了明显的细化与均匀化，γ/γ′共晶也发生了溶解并存在固溶微孔。热处理略微提高合金的抗拉强度，但明显提高了合金的延伸率。试样断裂为脆性断裂，铸态为正断型断裂，热处理态为切断型断裂。 关键词：镍基高温合金；凝固组织；热处理；拉伸性能 中图分类号：T 文献标志码：A 文章编号：1007-7545（2014）06-0000-00 ffects of Heat Treatment on Microstructure and Tensile Properties of Directional Solidification CMSX-6 Alloy JIA Zhi-hong, ZHU Xiang, MA Ming-ze, Xü Liang, WANG Shun-cheng, ZHAO Yu-tao (School of Material Science and Engineering, Jiangsu University, Zhenjiang 212013, Jiangsu, China) Abstract: Directional solidified nickel-base superalloy CMSX-6 specimens were prepared by high rate solidification in VDF-10 directional solidification furnace. Microstructure and tensile properties of the sample in different parts before and after heat treatment were studied respectively. The results show that the former solidified part is denser and primary dendrite arm spacing is narrow, with few eutectic structure and high tensile strength, low elongation. With almost fully homogeneous structure, the alloy no longer shows typical dendritic morphology after heat treatment, significant refinement and homogenization are achieved to γ phase, and γ/γ eutectic is dissolved with some homogenization micropores. Tensile strength is slightly improved after heat treatment, but elongation is obviously improved. The fracture mode of specimen is brittle fracture. The cast is of positive break type and the heat treatment state presents shear fracture. Key words: nickel-base superalloy; solidified structure; heat treatment; tensile properties 目前，由于单晶高温合金和定向凝固高温合金迅速发展，定向凝固高温合金已经成为现代航空发动机和燃气轮机叶片的主要材料。随着高温合金使用条件越来越苛刻，合金化程度越来越高，热处理成为高温合金制备中必不可少的工序[1-2]。决定高温合金力学性能的关键因素[3-5]主要是γ′相的形状、尺寸、分布和含量等。而对于镍基高温合金，使铸态中粗大的γ′相和γ/γ′共晶相全部或大部分固溶是热处理的主要作用，然后更为细小的γ′相可以在冷却过程中析出，实现成分均匀化[6]，以达到提高合金力学性能的目的。本文以CMSX-6合金为对象，运用金相分析、扫描电镜观察以及拉伸试验等方法，研究合金热