【摘要】 利用电子衍射背散射、透射电子显微观察、扫描电镜观察和室温拉伸试验对往复镦挤不同变形道次的2A66合金的组织和力学性能进行了检测和分析.结果表明,往复镦挤可以有效细化2A66铝锂合金组织,使组织更加均匀.随着往复镦挤变形道次增加,2A66铝锂合金中高密度位错逐渐向位错墙和亚晶界转变,粗大的第二相分布更均匀,弥散的β′相有部分回溶到2A66铝锂合金基体中.往复镦挤变形后2A66铝锂合金的塑性大幅提高,强度略有下降,其韧化主要是位错组态的变化、粗大的θ′相的均匀和细化以及弥散的β′相部分回溶的结果.更多还原

【Abstract】 Repetitive upsetting and extrusion(RUE)was firstly carried out on 2A66Al-Li alloy.Electron back-scatter diffraction(EBSD),transmission electron microscopy(TEM),scan electron microscopy(SEM),and room temperature tensile testing were then performed to investigate the microstructure characteristics and mechanical properties of 2A66Al-Li alloy.The results showed that RUE was effective in refining the microstructure of 2A66Al-Li alloy.With the increase of RUE pass numbers,high density dislocations in 2A66Al-Li alloy gradually transformed to dislocation walls and subgrain boundaries,distribution of large second phase(θ′)became more homogenous,and a part ofβ′dispersion dissolved into the aluminum-lithium alloy matrix.After RUE processing,the ductility improved greatly with a modest reduction in strengthening,as the toughening of the alloy was mainly attributed to the change of dislocation,the homogeneity and fragment ofθ′phase,and the dissolution ofβ′dispersion.更多还原