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analyzed and dislocation configurations were also observed by TEM. The mechanisms of cyclic hardening or softening during thermo-mechanical fatigue (TMF) tests were also discussed. Results showed...-aluminium alloy; thermo-mechanical fatigue; cyclic stress response; hysteresis loop; dislocation 1 Introduction Near-γ titanium aluminides are currently receiving much attention as candidates for high......
; 文献标志码:A Effects of Er and Yb elements on dislocation distributions in binary Al-Mg alloy SONG Min, HE Yue-hui (State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China) Abstract: The effects of Er and Yb elements on the dislocation distributions of a binary Al-Mg alloy were studied using a transmission electron microscope (TEM). It is shown......
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with the gliding of the partial dislocation, so, it is easy to realize the deformation. When the size of stack dislocations grows up, the local deformation stress ahead of the step gradually become big. When...; deformation; stack fault; dislocation 目前, 纳米金属晶体的变形机制尚不清楚. 当平均晶粒尺寸小于100nm时, 开动位错的应力接近理论剪应力. 对于面心立方金属, 开动位错的应力接近理论剪应力的晶粒临界尺寸大小为20~40nm[1], 因此, 在超细纳米晶体变形时位错是否形成并堆积, 以及位错是否导致塑性变形还不清楚[2......
摩擦过程中不同位错原子数目的统计分析 图9 摩擦过程中C~E阶段V形位错发展 Fig. 9 Generation and emission of V shape dislocation during scratch stage C-E characterized by centrosymmetry parameter 上文中针对摩擦阻力曲线峰值点所对应的微观原子组...变化曲线 Fig. 10 Evolution of number of partial dislocation atoms (a) and perfect dislocation atoms on scratch distance (b) 如3.2节所述,通过原子滑移矢量大小sα的判定可计算得到位错滑移相关的应变贡献,而对孪晶迁移相关的变形,采用Tucker[21]的定量化后处理方法来......
失和异号位错相消,而中,高应变幅下位错结构的回复机制主要表现为多边形化回复机制.粗晶纯铝经不同总应变幅疲劳后的DSC曲线测量结果与TEM观察结果基本一致. 关键词:纯铝;疲劳位错结构;热稳定性;退火;回复 中图分类号:TG146 Thermal stability of fatigue dislocation structures in coarse-grained pure aluminum... at different total strain amplitudes (Dεt/2) up to almost the same accumulated strain, and then annealed at different temperatures (200, 330 and 450 ℃) for 30 min. The fatigue dislocation structures as well......
动态压缩LY12铝合金微结构的XRD线形分析樊志剑1,宋振飞2,肖大武2,陈波0(1.四川省绵阳市工程物理研究院核物理与化学研究所2.中国工程物理研究院 流体物理研究所)摘 要:用Hopkinson杆实验装置在不同温度下对LY12铝合金进行动态压缩实验.采用XRD线形分析对压缩试样的微细观结构演化进行研究.由XRD的积分宽度确定试样中位错为刃型位错.衍射峰形的Fourier分析表明,在动态加载下,材料内部的位错密度在塑性流动的初期迅速趋于饱和,且随着测试温发的升高,位错密度呈递减趋势,同时亚结构的尺寸不断增加.......