文档介绍：中文摘要 I 摘要本文综合运用金相分析(OM) 、 X 射线荧光光谱分析(XRF) 、 X 射线衍射分析(XRD) 、透射电镜(TEM) 、扫描电镜(SEM) 及电子背散射分析(EBSD) 等分析测试手段,研究了 Mg-Y-Nd 合金的固溶时效硬化行为,揭示了析出物的形貌、晶体结构以及其与基体的取向关系,分析探讨了初始取向及析出物对合金单轴压缩变形行为和微观组织及织构演变的影响。论文主要研究结果如下: ①经过挤压或热轧加工后, Mg-Y-Nd 合金内部组织缺陷基本得到消除,挤压后合金晶粒细小,形成典型的(0001) 面丝织构,而热轧退火后晶粒粗化长大,形成{0001} 基面织构。 ② Mg-Y-Nd 合金在 210 ℃时效效果最好, 59 小时后达到峰值硬度 139Hv ,相对应的屈服和抗拉强度分别为 292Mpa 和 347Mpa 。 150 ℃样品在时效 46 小时后, 其硬化趋势已经不明显,并且强度提高不大,塑性下降明显。而 250 ℃、 280 ℃样品时效均在 8 小时附近出现峰值,随后硬度大幅下降,峰值样品强度没有明显提高。 ③ 150 ℃样品含有大量弥散细小的β’’( Mg 3 Nd )析出物,证实β’’与基体的取向关系为: ????? 100)Mg - (1 ∥' ' 100) - (1 [0001]Mg ∥' ' [0001] ββ; 210 ℃样品含有大量弥散细小的β’( Mg 12 NdY )析出物,使其具有最好的时效硬度效果,并且证实β’与基体的取向关系为: ?????(0001)Mg ∥' (001) 10]Mg - [10 ∥' [100] ββ; 250 ℃、 280 ℃样品主要含有粗大的β( Mg 14 Nd 2 Y ) 和β 1 析出物。④拉伸孪生是 Mg-Y-Nd 合金重要的塑性变形机制, 孪生的发生受合金初始取向和析出物的影响, C ∥ ED 样品比 C ⊥ ED 样品孪生比例高,相同取向下时效样品比挤压态样品孪生比例少,但是与AZ 系列镁合金相比,由孪生引起的软化现象不明显,常温下两种取向试样的强度差异不大。 关键词: Mg-Y-Nd 合金,析出相,变形机制,孪生,滑移 英文摘要 III ABSTRACT In the present work, comprehensive char acterization techniques including Optical Microscope (OM), X-Ray Fluorescence (X RF), Differential Scanning Calorimeter (DSC), X-ray diffraction (XRD), Scanni ng Electron Microscope (SEM), Energy Dispersive Spectrometer (EDS), Electr on Backscatter Diffraction (EBSD) and Transmission Electron Microscope (TEM ) were employed to study the ageing hardening behavior of Mg-Y-Nd alloy a nd reveal the morphology, structure of the precipitates and their orientati on relations with matrix. Moreover, the effects of initial texture and the precipitates on deformation behavior and on micros tructure and texture evolution were investigated and discussed. The main results are as follows: ① The internal defect structure has been removed after extrusion and hot rolling processing. The grain of the alloy was signi ficantly refined by extrusion and a (0001) fiber texture was formed. However, coar se grain was found af ter hot-rolling and annealing, and a (0001) basal texture was formed. ② The a