疲劳循环对A7005铝合金型材组织与力学性能的影响

发布时间：2019-02-13 04:18

【摘要】：采用扫描电镜、透射电镜、X射线衍射和室温拉伸等方法研究了A7005铝合金经不同疲劳循环加载次数对其组织和力学性能的影响。结果表明:A7005铝合金经0、104、105次疲劳循环后,位错密度从初始0.75×10~(14)m~(-2)上升至0.79×10~(14)m~(-2),抗拉强度和屈服强度逐步上升,并在10~5次循环时分别达到最大值402.72、341.92 MPa。经106、107次疲劳循环后,晶粒中开始出现位错胞,大量位错缠结在晶界附近,位错密度急剧上升至1.53×10~(14)m~(-2),晶内时效析出η'亚稳相会吸收溶解的Zn、Mg元素而长大粗化,以及因位错快速增殖而被溶解至基体中,η'亚稳相数量明显减少,降低了时效强化效果。疲劳区域边界上出现很多由第二相粒子脱落所引起的疲劳缺陷,材料的抗拉强度和屈服强度分别下降至396.57、328.07 MPa。
[Abstract]:The effects of different fatigue cyclic loading times on the microstructure and mechanical properties of A7005 aluminum alloy were studied by means of scanning electron microscope, transmission electron microscope, X-ray diffraction and room temperature tension. The results show that after 0104105 fatigue cycles, the dislocation density of A7005 aluminum alloy increases from 0.75 脳 10 ~ (14) m ~ (-2) to 0.79 脳 10 ~ (14) m ~ (-2), and the tensile strength and yield strength increase gradually. The maximum values were 402.72341.92 MPa. at 10 ~ 5 cycles, respectively. After 106107 cycles of fatigue, dislocation cells began to appear in the grains, a large number of dislocation entanglement occurred near grain boundaries, dislocation density increased sharply to 1.53 脳 10 ~ (14) m ~ (-2). 畏 'metastable phase precipitated in the crystal to absorb dissolved Zn,. Due to the growth and coarsening of Mg elements and the dissolution into the matrix due to the rapid growth of dislocations, the number of 畏 'metastable phases is obviously reduced, and the aging strengthening effect is reduced. There are many fatigue defects on the boundary of the fatigue zone caused by the shedding of the second phase particles. The tensile strength and yield strength of the material decreased to 396.57328.07 MPa., respectively.
【作者单位】：中南大学轻合金研究院;有色金属材料科学与工程教育部重点实验室;有色金属先进结构材料与制造协同创新中心;中南大学材料科学与工程学院;
【分类号】：TG146.21

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