(1. 兰州理工大学 省部共建有色金属先进加工与再利用国家重点实验室，兰州 730050； 2. 兰州理工大学 材料科学与工程学院，兰州 730050)
摘 要: 为了研究Ni, Nb, Ta, Ti和Mo元素对Co-8.8Al-9.8W基合金(摩尔分数，%)显微组织及γ′相溶解温度的影响，借助DSC和SEM等方法研究几种合金元素对合金γ/γ′两相显微组织形貌和γ′相转变温度的影响。结果表明：Ni和Mo元素降低γ′相的溶解温度，而Nb、Ta和 Ti元素提高了γ′相的溶解温度，且Ta的提高效果最明显。几种合金化合金经过(900 ℃, 50 h)时效处理后均形成γ/γ′两相组织。Ni和Mo元素能使合金中γ′相形貌由立方形变为近立方形或球形(如2Ni合金)，而其他合金元素并没有明显改变γ′相的立方形貌。Ni、Mo与Nb元素使合金中γ′相的体积分数减少，Ni减少的程度较为显著；但Nb、Ta和Ti元素使γ′相保持较高的体积分数。
关键字: Co-8.8Al-9.8W高温合金；γ′相；显微组织；体积分数
（1. State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals, Lanzhou University of Technology, Lanzhou 730050, China; 2. School of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou 730050, China）
Abstract:In order to study the influences of the Ni, Nb, Ta, Ti and Mo elements on microstructure and solution temperature of Co-8.8Al-9.8W ternary alloy (mole fraction, %), the effects of alloy elements on γ/γ two-phase microstructure and γ′ phase transition temperature were studied by means of DSC and SEM methods. The results show that Ni and Mo elements reduce the melting temperature of γ′ phase, and Nb, Ta and Ti elements improve γ′ phase solution temperature, and the effect of Ta is the most obvious. The γ/γ′ two-phase microstructure of alloys is abserved after aging treatment at 900 ℃ for 50 h. Ni and Mo can make the microstructure of γ′ phase by the cube into nearly cube or spherical (especially 2Ni alloy), and other alloying elements are not significantly change the γ′ cubic phase. Ni, Mo and Nb reduce the volume fractions of γ′ phase, Ni is significant reduction. But alloying additions (Nb,Ta,Ti) keep high volume fraction of γ′ phase.
Key words: Co-8.8Al-9.8W ternary alloy; γ′ phase; microstructure; volume fraction
