【摘要】 在定量统计析出相含量变化规律的基础上,研究了稳化处理时间对GH4706合金显微组织演化及力学性能的影响机理。结果表明:稳化处理后GH4706合金的主要析出相为小尺寸γ’-γ’’共析出相、大尺寸γ’相与η相。随稳化处理时间的延长,GH4706合金析出的η相由链状向胞状与针状演化,η相的析出长大逐渐消耗大尺寸γ’相,使得η相周围的析出相贫化区逐渐粗化。稳化处理1~3 h可改善GH4706合金的室温、高温强度与持久寿命,但牺牲冲击韧性。当稳化时间延长至5 h时,GH4706合金的高温强度、韧性与持久性能均出现劣化现象,因此GH4706大尺寸涡轮盘锻件不宜采用长时稳化处理。更多还原

【Abstract】 Based on the statistic of the precipitation content, the effect of stabilization time on precipitation behavior and mechanical properties of GH4706 alloy were investigated. Results show that the main precipitates of GH4706 Alloy after stabilization treatment are γ′-γ′′ of small size and γ′ as well as η of large size. η phase precipitated during stabilization treatment changes from chains or rod morphology to cellular and acicular with longer stabilization time. Furthermore, the fraction of η phase increases with the increase of stabilization time, and the precipitation free zone tends to be wider owing to the reaction between large γ’ phase and η phase. The RT and 650 oC tensile strength and rupture life of GH4706 alloy are improved after stabilization treatment at 845 oC for 1~3 h at the expense of compact toughness. The deterioration of 650 oC tensile strength, toughness and rupture properties occurs as the stabilization time increases to 5 h. Therefore, it is unsuitable to adopt a long-term stabilization treatment for the large GH4706 gas turbine disc.更多还原