YE Han,LAI Liu-sheng,LI Jun,LIU Sen-zhong,XIONG Hui.Surface Properties of 7075 Aluminum Alloy Workpieces after Ultrasonic Burnishing Processing[J],47(2):8-13 |
Surface Properties of 7075 Aluminum Alloy Workpieces after Ultrasonic Burnishing Processing |
Received:July 03, 2017 Revised:February 20, 2018 |
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DOI:10.16490/j.cnki.issn.1001-3660.2018.02.002 |
KeyWord:ultrasonic burnishing 7075 aluminum alloy rolling reduction surface roughness microhardness residual comprehensive stress |
Author | Institution |
YE Han |
School of Mechatronic Engineering, Nanchang University, Nanchang , China |
LAI Liu-sheng |
School of Mechatronic Engineering, Nanchang University, Nanchang , China |
LI Jun |
School of Mechatronic Engineering, Nanchang University, Nanchang , China |
LIU Sen-zhong |
School of Mechatronic Engineering, Nanchang University, Nanchang , China |
XIONG Hui |
School of Mechatronic Engineering, Nanchang University, Nanchang , China |
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Abstract: |
The work aims to explore effects of ultrasonic burnishing (UB) technology on surface properties of 7075 aluminum alloy workpieces. Finish turning and ultrasonic burnishing were applied to rotating bar specimens made from 7075 aluminum alloy successively. Effects of rolling reduction among process parameters on surface properties of the specimens including surface roughness, surface microhardness, surface microstructure and surface residual stress were investigated with roughness tester, microhardness tester, metalloscope and X-ray diffraction stress analyzer before and after the finish turning and UB. After finish turning, surface roughness of the specimens decreased from 0.976 μm to 0.047 μm, surface microhardness of the specimens increased from 105.6HV0.2 to 119HV0.2 (increased by 15%). After UB, surface grain of the specimens was approximate the same as that of the central grain. The surface grain of the UB specimens was considerably refined compared to the central grain after UB. Residual compressive stress was all induced on the surface layer, the maximum value appeared on the surface and the residual compressive stress layer was 1.75 mm deep. The residual compressive stress on the top surface was up to -174.0 MPa, but it tended to decrease as a whole as distance from the top surface increased. By comparing the specimens receiving finish turning and UB, it can be concluded that UB can remarkably reduce surface roughness of the specimens, dramatically refine surface grain, noticeably improve surface microhardness, improve distribution of residual stress and introduce certain depth of residual compressive stress. |
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