论文部分内容阅读
采用疲劳试验、透射电镜、扫描电镜及X射线衍射仪等方法研究了2124-T851铝合金厚板不同参数孔挤压强化后疲劳寿命与显微组织的变化。结果表明:孔挤压强化后试样的疲劳寿命先随挤压量的增大而升高,随后又迅速降低,挤压量为0.4 mm时疲劳寿命达到峰值,较未强化增加12.66倍;组织观察结果表明孔挤压强化后,在孔壁强化层内形成了位错胞状结构和残余压应力,并且随挤压量增大先迅速增加然后趋于平缓,强化层的形成可以有效延缓疲劳裂纹的扩展速率;同时,适当的孔挤压强化可改善表面粗糙度,降低裂纹萌生几率,从而提高材料的疲劳寿命。
The fatigue life, microstructure and microstructure of 2124-T851 aluminum alloy plate under different parameters were studied by means of fatigue test, transmission electron microscope, scanning electron microscopy and X-ray diffraction. The results show that the fatigue life of the sample increases with the increase of the extrusion pressure first, and then decreases rapidly. When the extrusion pressure is 0.4 mm, the fatigue life reaches the peak value, which increases by 12.66 times compared with that without reinforcement. The observation results show that the dislocation cellular structure and residual compressive stress are formed in the hole wall reinforcement layer after extrusion and strengthening, and then increase rapidly with the increase of extrusion amount and then tend to be gentle. The formation of strengthening layer can effectively delay the fatigue crack Of the expansion rate; the same time, appropriate hole extrusion strengthening can improve the surface roughness and reduce the probability of crack initiation, thereby enhancing the fatigue life of the material.