(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)
摘 要: 采用扫描电镜、透射电镜、X射线衍射、拉伸实验研究长时时效对GH625合金析出相及其拉伸性能的影响，并采用绝热法和Rietveld全谱拟合法对合金在720 ℃长时时效过程中主要析出相的体积分数进行了定量分析，进一步研究了析出相的体积分数与合金拉伸性能的关系。结果表明：GH625合金在720 ℃长时间时效过程中存在着γ相→γ′相→γ″相→δ相的转变；随着时效时间的延长，γ″相与δ相的体积分数始终在增大，而γ′相的体积分数则先增加后减少。析出相对GH625合金的拉伸性能有较大的影响。γ′相和γ″相的析出能够提高合金的强度，但大量尺寸过大的γ″相对合金的塑性不利；大量δ相的析出和长大使得合金的强度减小，但屈服强度比有所增加，而合金塑性则大幅降低。
关键字: GH625合金；析出相；长时时效；定量分析；拉伸性能
（State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050, China）
Abstract:The effect of long-time aging on the precipitated phase and tensile properties of GH625 alloy was investigated by scanning electron microscopy(SEM), transmission electron microscopy(TEM), X-ray diffractiometry and tensile tests. Using heat insulation method and Rietveld full spectrum fitting method, the volume fractions of the main precipitated phases of GH625 alloy during thermal aging were quantitatively analyzed. The relationship between volume fraction of precipitated phases and tensile properties was further analyzed. The results show that the γ phase in the microstructure of GH625 alloy transforms into γ′ phase, γ″ phase and δ phase in sequence during long-time aging at 720 ℃.With aging time prolonging, the volume fractions of γ″ phase and δ phase increase, and the volume fraction of the γ′ phase increases firstly and then decreases. The tensile properties of GH625 alloy are significantly affected by the precipitated phases. The γ′ phase and γ″ phase can improve the strength of the alloy, but the γ″ phase with large size is not good to the plasticity of the alloy. The precipitation and growth of the large amount of δ phase decrease the strength of the alloy, but increase the yield ratio, while the plasticity of the alloy decreases greatly.
Key words: GH625 alloy; precipitated phase; long-time aging; quantitative analysis; tensile properties
