热处理和锻造工艺对Nimonic91高温合金晶粒度和力学性能的影响

Effect of Heat Treatment and Forging Processes on Grain Size and Mechanical Properties of Nimonic91 Superalloy

经固溶和时效处理的Nimonic 91高温合金￠83 mm棒材力学性能不合格。为此,对同样直径的Nimonic 91合金棒材进行了热处理和锻造工艺试验:1050~1210℃保温0.5~4 h空冷固溶处理,1150℃×4 h空冷固溶处理随后850℃×(6~16)h空冷时效处理,1150℃×4 h空冷固溶处理随后850℃×16 h炉冷和850℃×16 h空冷再700~830℃保温2~16 h空冷时效处理,以及1100~1160℃锻造和锻造后1150℃固溶处理。检测了合金的晶粒尺寸和力学性能。结果表明:1050~1120℃固溶处理的合金晶粒度变化不大,1130~1210℃固溶处理的合金0级或00级晶粒增多;1150℃保温0.5~4 h固溶处理的合金晶粒随着固溶时间的延长逐渐粗化;固溶处理后850℃时效6~16 h的合金力学性能变化不大,850℃时效后炉冷或700~830℃再次时效的合金抗拉强度和屈服强度提高,断后伸长率下降;1100~1160℃锻造随后1150℃固溶处理的合金,随着锻造温度的升高,晶粒尺寸变化不大。

Nimonic 91 superalloy bar 83 mm in diameter exhibited unqualified mechanical property after solution treating and aging.For this reason,the Nimonic 91 superalloy bar with the same diameter was subjected to heat treating and forging process tests,among which were:solution treating at 1050 to 1210℃for 0.5 to 4 h and air cooling,solution treating at 1150℃for 4 h then air cooling and aging at 850℃for 6 to 16 h then air cooling,solution treating at 1150℃for 4 h and air cooling followed by aging at 850℃for 16 h and furnace cooling,and aging at 850℃for 16 h and air cooling and again aging at 700 to 830℃for 2~16 h followed by air cooling,as well as forging at 1100~1160℃and forging followed by solution treating at 1150℃.The superalloy was tested for grain size and mechanical properties.The results showed that(a)the superalloy solution treated at 1050 to 1120℃had a little change in grain size;(b)the superalloy solution treated at 1130 to 1210℃increased in grains of 0 grade or 00 grade sizes;(c)grains in the superalloy solution treated at 1150℃for 0.5 to 4 h coarsened gradually with the increase in solution time;(d)the superalloy solution treated then aged at 850℃for 6 to 16 h had less change in mechanical properties,and the superalloy aged at 850℃then furnace cooled,or again aged at 700 to 830℃increased in tensile and yield strengths,and decreased in elongation;and(e)the superalloy forged at 1100 to 1160℃then solution treated at 1150℃had no significant change in grain size with the rise in forging temperature.