(1. 哈尔滨工业大学 材料科学与工程学院,哈尔滨 150001;
2. 哈尔滨工业大学 金属精密热加工国家级重点实验室,哈尔滨 150001;
3. 重庆长安汽车股份有限公司,重庆 404100)
摘 要: 研究分别添加0.3%、0.7%、1.0%W(摩尔分数)对高铌TiAl合金组织和力学性能的影响。结果表明:W的添加不改变合金的凝固路径,不影响合金的室温相组成;随W添加量的增加,合金中Nb和Al的元素偏析程度提高,添加1.0%W时,Al元素偏析明显;W的添加提高TiAl合金的显微硬度,W含量的变化对显微硬度的影响较小;适量的添加W可提高合金的室温压缩强度,添加0.7%W合金的强度达到最大,为1821 MPa,压缩率为24.47%,过量的W(1.0%)将导致合金组织偏析严重,恶化合金的性能。
关键字: TiAl合金;钨;显微组织;力学性能
(1. School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China;
2. National Key Laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin 150001, China;
3. Chongqing Changan Automobile Co., Ltd., Chongqing 404100, China)
Abstract:The effects of the addition of 0.3%, 0.7%, 1.0%W (mole fraction) on the microstructure and mechanical properties of high-Nb TiAl alloy were studied. The results show that the W alloying doesn’t change the alloy solidification path, has no effect on the room temperature phase composition of high-Nb TiAl alloy. With the increase of W content, the segregation degree of Nb and Al element is enhanced, and the macrosegregation of Al turns striking with 1.0% W addition. Tungsten alloying boosts the microhardness of TiAl alloy, while this boost does not rely on the W content variation. Appropriate W addition can facilitate the room temperature compression strength, the strength achieves maximum value as 1821MPa and the compressibility reaches 24.47% with 0.7% W addition. Nevertheless, excessive W addition (1.0%) will deteriorate the mechanical property owing to severe segregation of Nb, W and Al.
Key words: TiAl alloy; W; microstructure; mechanical property