用SEM、TEM、EDS和ICP-AES等方法进行微观组织分析,用冲击试验机测定冲击性能,研究了LF9镍基合金经(800~1 040)℃×1 h固溶水冷处理后γ′相和η相的变化及对合金冲击性能的影响.结果表明:合金中的γ′相在高温下发生长大,原始锻态γ′相的平均尺寸约20 nm,980 ℃固溶时平均尺寸约120 nm,而1 020 ℃时γ′相完全溶解;820 ℃时次生析出η相沿晶界平行往外生长,在η相两侧形成贫γ′区,约980 ℃时析出量达到最多,约1 040 ℃时完全溶解;贫γ′区的微塑性区能减缓裂纹的扩展速率,改善合金的冲击性能;η相的析出数量增多和尺寸增大降低了合金的冲击性能.

The changes of γ′ and η phases in LF9 nickel-based alloy after solution treatment at 800-1 040 ℃ for 1 h and then water quenched were studied by SEM,TEM,EDS and ICP-AES methods and the impact toughness of the alloy was measured using impact tester.The results showed that the γ′ phase in the alloy would grow up at high temperatures.For example,the average size of γ′ phase in original forging microstructure was about 20 nm,became 120 nm at 980 ℃ and dissolved completely at 1 020 ℃.The secondary parallel η phase grew up outward along grain boundaries at 820 ℃,reached peak value at 980 ℃ and dissolved completely at 1 040 ℃.At the same time,the γ′-depleted-zone appeared beside the growing η phase.The microplastic effect of the γ′-depleted-zone reduced the crack diffusion rate and thus improved the alloy ductility.However,the increase of the precipitation quantity and size of the η phase decreased the impact tonghness of the alloy.