2099合金的熱變形行為及組織演化Hot deformation behavior and microstructure evolution of 2099 alloy

采用熱壓縮試驗、方差分析和TEM技術(shù)研究變形條件對2099合金流變行為的影響規(guī)律和組織演化特征。結(jié)果表明：隨著應(yīng)變的增加，2099合金流變應(yīng)力經(jīng)歷了過渡變形和穩(wěn)態(tài)變形兩個階段。在顯著性水平為0.01條件下，變形溫度和應(yīng)變速率對2099合金流變應(yīng)力的影響高度顯著，表明該合金為正的應(yīng)變速率和負的變形溫度敏感性材料。且隨著應(yīng)變的增加、變形溫度的升高和應(yīng)變速率的降低，合金組織依次經(jīng)歷了無規(guī)則的位錯纏結(jié)→多邊形化→晶界弓出形核+亞晶合并→再結(jié)晶晶粒長大過程。當變形溫度為460 ℃、應(yīng)變速率為0.01 s^-1、應(yīng)變量為1.1時，合金可獲得細小的再結(jié)晶組織。

The effects of deformation conditions on flow behaviors and microstructure evolution characteristics of 2099 alloy were investigated by hot compression tests, variance analysis and TEM technology. The results show that, the flow stress of 2099 alloy experiences two stages with the increase of strains, namely, the transition deformation stage and the steady deformation stage. The effects of temperatures and strain rates on the flow stress are significant under the significance level of 0.01, which indicates that 2099 alloy is a positive strain rate sensitive and negative temperature sensitive materials. The microstructure of 2099 alloy experiences irregular dislocation tangles → polygonization → grain boundaries bulging + subgrains coalescence → dynamic recrystallization grain growth with increasing the strains and temperatures and decreasing the strain rates. And the fine recrystallized microstructure of 2099 alloy can be obtained under the deformation conditions of temperature 460 ℃, strain rate 0.01 s^-1 and stain 1.1.

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