高温处理对LF9合金组织及力学性能的影响

Effects of High-temperature Treatment on Microstructure and Mechanical Properties of LF9 Alloy

研究了不同热处理制度下η相和γ'相在LF9合金中的析出特征及其对合金性能的影响。结果表明:合金在820～940℃保温1 h水冷后,室温冲击韧度随加热温度的升高而提高,在940～980℃随加热温度的升高而降低,在980～1040℃随加热温度的升高,韧性急剧提高,这是合金中η相、γ'相以及贫γ'区综合作用的结果;合金在800℃时,γ'相尺寸约30 nm,随温度升高,γ'相长大,约980℃时尺寸达到最大值(120 nm),约1020℃时,γ'相完全回溶;820℃时次生η相从晶界析出并以片层形态沿晶界平行往晶内生长,约1040℃时,η相完全回溶。

The separation characteristic of η phase and γ ＇ phase in LF9 alloy under different heat treatment system and its influence on the mechanical performance of the alloy was studied.The results show that the toughness increases with the increase of heating temperature at 820 ℃～940 ℃ for 1 h then water cooling;decreases at 980 ℃～1040 ℃ and substantially increases at 980 ℃～1040 ℃.This is the results of combination action of η phase,γ ＇ phase and zone with little γ ＇ phase.The size of γ ＇ phase is about 30 nm at 800 ℃,the size of γ ＇ phase increases with the increase of temperature.The size of γ ＇ phase reaches 120 nm at 980 ℃.The γ ＇ phase completely dissolves at 1020 ℃.The secondary η phase separates and grows along grain boundary at 820 ℃.The η phase completely dissolves at 1040 ℃.