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研究了不同固溶冷却介质(油、空、棉)及之后的时效处理对优质GH738(HQGH738)合金组织及力学性能的影响。分别利用光学金相显微镜(OM)和场发射扫描电镜(FESEM)对热处理各阶段合金的晶粒组织及γ′相分布情况进行观察,同时检测热处理各阶段拉伸强度。结果表明:冷却介质对HQGH738合金晶粒尺寸无影响,而主要影响一次及二次γ′相的回溶及析出行为,进而影响合金的性能。固溶阶段,随冷速的提高(油淬>空冷>棉冷),合金中二次γ′相减少,尺寸越小,固溶后合金抗拉强度降低。经过稳定化处理后,3种冷却方式下合金强度顺序不变,但差值减小。再经过双时效后,三者抗拉强度相当。冷速越快,一次γ′相粗化越慢,从而在双时效过程中析出更多的细小二次γ′相,最终合金的屈服强度随冷速的增加而增强。
The effects of different solid solution cooling media (oil, air, cotton) and aging treatment on the microstructure and mechanical properties of high quality GH738 (HQGH738) alloy were studied. The microstructure and γ ’phase distribution of the alloy during each stage of heat treatment were observed by optical microscope (OM) and field emission scanning electron microscope (FESEM), respectively. The tensile strength of each stage of heat treatment was also measured. The results show that the cooling medium has no effect on the grain size of the HQGH738 alloy, but mainly affects the solution and precipitation behavior of the primary and secondary γ ’phases, thereby affecting the properties of the alloy. With the increase of cooling rate (oil quenching> air cooling> cotton cooling), the secondary γ ’phase decreases and the smaller the size, the lower the tensile strength of the alloy after solution treatment. After stabilization treatment, the strength of the three kinds of cooling alloy under the same order of magnitude, but the difference decreases. After a double aging, the three tensile strength quite. The faster the cooling rate, the slower the γ ’phase coarsening, so more fine secondary γ’ phases are precipitated during the double aging process. The final alloy yield strength increases with the increase of cooling rate.