Improvement in fatigue performance of friction stir welded A6061-T6 aluminum alloy by laser peening without coating
Improvement in fatigue performance of friction stir welded A6061-T6 aluminum alloy by laser peening without coating
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DOI：
10.1016/j.matdes.2011.10.053
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发表时间：
2012-04
影响因子：
8.4
通讯作者：
Y. Sano;K. Masaki;T. Gushi;T. Sano
中科院分区：
文献类型：
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作者：
Y. Sano;K. Masaki;T. Gushi;T. Sano
对厚度为3 mm的A6061-T6铝合金搅拌摩擦焊板的疲劳试件进行了激光喷丸处理。牙冠、牙根分别用倍频激光脉冲进行冲击，脉冲能量为60mJ，峰值功率密度为2GW/cm2。在应力比为R=−1的平面弯曲疲劳试验中，研究了应力比R=LPwC对疲劳性能的影响。结果表明，未焊接试件(母材)在107次疲劳循环下的疲劳强度为110 Mpa，尽管激光脉冲直接照射到试件的裸露表面增加了表面粗糙度，但LPwC使强度提高了60 Mpa。同时，FSWED试件的疲劳强度为90 Mpa，LPwC可将其提高30~120 Mpa。这一增量是BM的一半，但LPwC后的FSWed试件的疲劳强度高于BM。并对表面粗糙度、硬度和残余应力进行了评定和表征。
The authors have applied laser peening without coating (LPwC) to fatigue specimens cut out from friction stir welded (FSWed) A6061-T6 aluminum alloy plates with a thickness of 3mm. Both crown and root sides of the specimens were peened by laser pulses with an energy of 60mJ and a peak power density of 2GW/cm2from a frequency-doubled Nd:YAG laser. The effects on the fatigue properties were studied through plane bending fatigue tests with a stress ratio of R=−1. The results showed that the fatigue strength of unwelded specimens (base material; BM) was 110MPa at 107cycles and LPwC enhanced the strength by 60MPa in spite of increase in surface roughness due to the direct irradiation of the laser pulses to the bare surface of the specimens. Meanwhile the fatigue strength of FSWed specimens was 90MPa and LPwC enhanced it by 30MPa to 120MPa. This increment is a half compared to that in the BM, however the fatigue strength of the FSWed specimens after LPwC was higher than that of the BM. The surface roughness, hardness and residual stress were assessed and characterized as well.