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以2090铝锂合金作为参照,细致地观察了2090+Ce铝锂合金时效组织特征及其形成规律。首次利用图形分析等手段,对比研究了2090和2090+Ce铝锂合金中沉淀相尺寸分布规律,通过对两合金中δ′相和T_1相生长、粗化行为的研究,探讨了微量稀土Ce的作用机制。研究中发现添加微量稀土Ce,对时效初期δ′相的生长有一定的抑制作用,而对T_1相的析出却有一定的促进作用,其T_1相表现出较小的长厚比。在深入观察2090+Ce合金位错组态特征的基础上,计算了δ′相、T_1相的强化贡献及其综合效应。发现合金中位错组态随时效条件发生变化。T_1相与位错间的交互作用形式是切过和绕过的混合型,两相复合强化形式与时效时间有关。对比研究了2090和2090+Ce铝锂合金板材屈服强度各向异性及其形变织构、人工时效等因素的影响作用,探究了沉淀相强化作用与两合金板材屈服强度各向异性间的内在联系以及微观形变和断裂特征随取向角、时效条件的变化。结果表明T_1相等沉淀相对铝锂合金屈服强度各向异性以及断裂特征有着直接的影响,并提出了一修订的塑性内合物模型。
Taking 2090 Al-Li alloy as reference, the aging characteristics and formation regularity of 2090 + Ce Al-Li alloy were carefully observed. For the first time, the size distribution of precipitates in 2090 and 2090 + Ce Al-Li alloys was comparatively studied by means of graphic analysis. The growth and coarsening behavior of δ ’phase and T_1 phase in both alloys were studied. The effects of rare earth Ce Mechanism. It was found that the addition of trace rare earth Ce could inhibit the growth of δ ’phase early in the aging process and promote the precipitation of T_1 phase, while the T_1 phase showed a smaller aspect ratio. Based on the in-depth observation of the dislocation configuration features of 2090 + Ce alloy, the enhanced contributions of δ ’phase and T_1 phase and their combined effects were calculated. It was found that the dislocation configuration changed with the aging conditions. The interaction between the T_1 phase and the dislocations is a mixed type of cut and bypassed, and the two phases are related to the aging time. The effects of anisotropy of yield strength, deformation texture and artificial aging of 2090 and 2090 + Ce Al-Li alloy plates were compared. The intrinsic relationship between the strengthening effect of precipitation phase and the yield strength anisotropy of the two alloy plates was investigated. And microscopic deformation and fracture characteristics with the orientation angle, aging conditions change. The results show that the equivalent precipitation of T_1 has a direct effect on the yield strength anisotropy and fracture characteristics of Al-Li alloy, and a revised model of the plastic inclusion is proposed.