Fatigue strength improvement of Mg alloy AZ61 by double ultrasonic shot peening
Fatigue strength improvement of Mg alloy AZ61 by double ultrasonic shot peening
复制标题
双超声波喷丸提高镁合金AZ61疲劳强度
DOI：
10.1299/transjsme.16-00218
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
K. Hattori
中科院分区：
文献类型：
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作者：
T. Kakiuchi;Y. Uematsu;K. Sanada;F. Nakao;K. Hattori
采用双超声波喷丸处理（USP）和其他条件下喷丸处理的镁合金AZ61进行旋转弯曲疲劳试验，研究喷丸处理（SP）对疲劳行为的影响，并获得疲劳强度的高且稳定的提高。单次USP处理在喷射直径0.6mm、1.0mm、2.0mm、覆盖率80%、200%、300%的条件下进行。使用 Zirblast B120 弹丸进行空气喷射 SP，覆盖率为 300%。双USP第一次处理在弹丸直径1.0mm、覆盖率300%的条件下进行，然后第二次处理在弹丸直径0.6mm、覆盖率300%的条件下进行。对每个试样的显微组织、硬度、残余应力和表面粗糙度进行了研究和比较。经过低覆盖率和高覆盖率大弹丸直径处理的USP试样的疲劳强度有所下降，而其他USP和空气SP试样的疲劳强度则有所提高。与母材以及其他单 USP 和空气 SP 样本相比，双 USP 实现了高疲劳强度的提高。认为双USP试件疲劳强度的提高归因于第一次处理中硬度和残余压应力的充分增加以及第二次处理中表面粗糙度的降低以及薄加工软化层的去除或改性。
Rotary bending fatigue tests using magnesium alloy AZ61 treated by double ultrasonic shot peening (USP) and peening under other conditions were performed to investigate the effect of shot peening (SP) on the fatigue behavior and to obtain high and stable improvement in fatigue strength. The single USP treatment was conducted under the condition of the shot diameter of 0.6 mm, 1.0 mm and 2.0 mm and the coverage of 80 %, 200 % and 300 %. The air blast SP was conducted using Zirblast B120 shot and under the coverage of 300 %. The first treatment of the double USP was conducted under the condition of the shot diameter of 1.0 mm and the coverage of 300 %, and then the second treatment was conducted under the condition of the shot diameter of 0.6 mm and the coverage of 300 %. Microstructures, hardness, residual stress and surface roughness of each specimen were investigated and compared. The fatigue strength of USP specimens which were treated under the low coverage and the high coverage with the large shot diameter was decreased, while that of the other USP and the air SP specimens was improved. High fatigue strength improvement was achieved by the double USP compared with the base metal and the other single USP and air SP specimens. It is considered that the improvement of fatigue strength of double USP specimen is attributed to the enough increase in hardness and compressive residual stress in the first treatment and the decrease of surface roughness and the removal or the modification of the thin work-softened layer in the second treatment.