时效工艺对冷变形多相紧固件GH350合金组织与性能的影响

 利用光学显微镜和扫描电镜(SEM)分析,研究了冷拔态GH350(AEREX350)合金中η-Ni₃Ti相的时效析出规律以及对合金高温拉伸性能的影响。研究发现,冷拔态GH350合金中η-Ni₃Ti相在780~1 060 ℃温度范围内析出,且呈两种形态。晶界片状η相在780~1 060 ℃温度范围内均可析出,但在850~1 060 ℃温度区间,除晶界η相外,在晶内沿(111)面呈魏氏体形态析出片状η相。冷变形GH350合金在980 ℃开始发生再结晶,1 010 ℃可完全再结晶。对二阶时效后冷变形GH350合金的高温拉伸实验表明,随着一阶时效温度的升高,合金的高温塑性增加,强度降低。

Influence of Aging Treatment on Microstructure and Properties of Cold-drawn Alloy GH350

The influence of aging treatment on the precipitation behavior of η-Ni3Ti phase and high temperature tensile properties for cold-drawn alloy GH350(AEREX350) is investigated by means of optical microscopy,scanning electron microscopy(SEM)and 730 ℃ tensile tests.It is found that η phase appears at grain boundaries or grain interiors during 780-1 060 ℃ aging in cold-drawn alloy GH350.The precipitation temperature of grain boundary η phase ranges from 780 ℃ to 1 060 ℃,while a Widmanstttan morphology of η phase aligning along(111) crystallographic planes of the matrix is formed at 850 ℃ to 1 060 ℃.Experimental results also show that cold-drawn alloy GH350 begins to recrystallize at 980 ℃,and has a complete recrystallization at 1 010 ℃.730 ℃ tensile tests of cold-drawn alloy GH350 after a two-stage aging show that high temperature ductility of the alloy is improved,while the strength decreases with increase of the first stage aging temperature.