贺柏涵,周文龙,程旭,等.7A65铝合金喷丸强化表面完整性及疲劳性能[J].精密成形工程,2023,15(6):1-10.
HE Bai-han,ZHOU Wen-long,CHENG Xu,et al.Surface Integrity and Fatigue Properties of Shot Peening Strengthened 7A65 Aluminum Alloy[J].Journal of Netshape Forming Engineering,2023,15(6):1-10. |
| 7A65铝合金喷丸强化表面完整性及疲劳性能 |
| Surface Integrity and Fatigue Properties of Shot Peening Strengthened 7A65 Aluminum Alloy |
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| DOI：10.3969/j.issn.1674-6457.2023.06.001 |
| 中文关键词: 7A65铝合金 疲劳寿命 喷丸强化 表面完整性 表面粗糙度 残余应力 |
| 英文关键词: 7A65 aluminum alloy fatigue life shot peening surface integrity surface roughness residual stress |
| 基金项目:国家自然科学基金(51975084);辽宁省自然科学基金(2022–YKLH–04);中央高校基本科研业务费专项(DUT19LAB16);辽宁省“兴辽英才计划”(XLYC1902084) |
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| 中文摘要: |
| 目的 以7A65高强度铝合金为研究对象，研究喷丸强度、弹丸介质(铸钢丸和陶瓷丸)对靶材疲劳性能的影响规律。方法 利用扫描电镜、激光共聚焦显微镜、X射线衍射仪等仪器表征喷丸强化7A65铝合金表面完整性和疲劳失效断口，分析喷丸工艺参数与疲劳性能、断裂模式的相关性。结果 喷丸强化后铝合金表面粗糙化严重，表面粗糙度从初始0.622 μm增加至4.736 μm(铸钢丸、喷丸强度为0.22 mmA)，并出现褶皱损伤;在相同喷丸强度下陶瓷丸喷丸表面粗糙度较低，无褶皱损伤。2种弹丸在金属表面引入的残余应力场基本相同，残余压应力层深约300 μm，最大残余压应力值为−480.6 MPa，其产生位置为距离表面75 μm处(喷丸强度为0.22 mmA)。铝合金疲劳性能对铸钢丸介质敏感性较高，当喷丸强度较低(0.11 mmA)时喷丸强化效果最佳，疲劳寿命是原始寿命的5倍多，疲劳源从表面转移至次表面(500 μm);当喷丸强度增至0.22 mmA时，裂纹源向表面靠近，疲劳寿命为原始寿命的2倍。铝合金疲劳性能对陶瓷丸介质敏感性较低，在喷丸强度为0.11~0.22 mmA时疲劳寿命较为稳定，在喷丸强度为0.11 mmA时疲劳寿命最高，为原始寿命的7倍。结论 7A65高强度铝合金经喷丸强化后疲劳寿命显著提升，强化效果受弹丸介质影响，陶瓷丸介质强化效果更好、喷丸强化工艺窗口更宽。 |
| 英文摘要: |
| The work aims to study the effects of shot peening strength and shot medium (cast steel shot and ceramic shot) on fatigue properties of target with 7A65 high strength aluminum alloy as the research object. The surface integrity and fatigue failure fracture of the target were characterized by scanning electron microscopy, laser confocal microscope, X-ray diffractometer and EBSD. The correlations between shot peening process parameters, fatigue properties and fracture modes were analyzed. After shot peening, the surface roughness of aluminum alloy was serious, the Ra increased from 0.622 μm to 4.736 μm (the shot peening strength of cast steel shot was 0.22 mmA), and fold damage appeared. Under the same shot peening strength, the surface roughness of ceramic shot was lower and there was no fold damage. The residual stress field introduced by the two projectiles on the metal surface was basically the same. The depth of the compressive residual stress layer was about 300 μm, and the maximum residual stress was −480.6 MPa, and the distance from the surface was 75 μm (the shot peening strength was 0.22 mmA). The fatigue performance of aluminum alloy was sensitive to the cast steel shot medium, and the best strengthening effect was achieved when the shot peening strength was low (0.11 mmA). The life was more than 5 times that of the original state. And the crack source transferred from the surface to the secondary surface (500 μm). When the shot peening strength was increased to 0.22 mmA, the crack source was close to the surface, and the fatigue life was twice as long as the original state. The fatigue performance of aluminum alloy was less sensitive to ceramic shot medium, and the fatigue life was relatively stable when the shot peening strength was 0.11-0.22 mmA. The fatigue life was the highest at 0.11 mmA, which was 7 times of the original state. Therefore, the fatigue life of 7A65 aluminum alloy is significantly improved after shot peening. The strengthening effect is affected by the projectile medium. The ceramic shot medium has better strengthening effect and the shot peening process window is wider. |
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