(蘭州理工大學(xué) 省部共建有色金屬先進(jìn)加工與再利用國(guó)家重點(diǎn)實(shí)驗(yàn)室，蘭州 730050)
摘 要: 采用掃描電鏡、透射電鏡、X射線衍射、拉伸實(shí)驗(yàn)研究長(zhǎng)時(shí)時(shí)效對(duì)GH625合金析出相及其拉伸性能的影響，并采用絕熱法和Rietveld全譜擬合法對(duì)合金在720 ℃長(zhǎng)時(shí)時(shí)效過(guò)程中主要析出相的體積分?jǐn)?shù)進(jìn)行了定量分析，進(jìn)一步研究了析出相的體積分?jǐn)?shù)與合金拉伸性能的關(guān)系。結(jié)果表明：GH625合金在720 ℃長(zhǎng)時(shí)間時(shí)效過(guò)程中存在著γ相→γ′相→γ″相→δ相的轉(zhuǎn)變；隨著時(shí)效時(shí)間的延長(zhǎng)，γ″相與δ相的體積分?jǐn)?shù)始終在增大，而γ′相的體積分?jǐn)?shù)則先增加后減少。析出相對(duì)GH625合金的拉伸性能有較大的影響。γ′相和γ″相的析出能夠提高合金的強(qiáng)度，但大量尺寸過(guò)大的γ″相對(duì)合金的塑性不利；大量δ相的析出和長(zhǎng)大使得合金的強(qiáng)度減小，但屈服強(qiáng)度比有所增加，而合金塑性則大幅降低。
關(guān)鍵字: GH625合金；析出相；長(zhǎng)時(shí)時(shí)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
