Surface Characterizations of Fretting Fatigue Damage in Aluminum Alloy 7075-T6 Clamped Joints: The Beneficial Role of Ni-P Coatings.
Surface Characterizations of Fretting Fatigue Damage in Aluminum Alloy 7075-T6 Clamped Joints: The Beneficial Role of Ni-P Coatings.
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DOI：
10.3390/ma9030141
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发表时间：
2016-02-27
期刊：
影响因子：
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通讯作者：
Ibrahim RN
中科院分区：
文献类型：
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作者：
Oskouei RH;Barati MR;Ibrahim RN
本文旨在通过XRD、表面轮廓仪和SEM分析表征铝合金7075-T6双搭接螺栓连接件微动疲劳的表面损伤。主要关注的是损伤区的表面粗糙度和化学相组成沿着与识别微动疲劳裂纹萌生在材料的表面。在相同的循环载荷下，当接头用更高的拧紧力矩夹紧时，磨损区的表面粗糙度增加。此外，在摩擦磨损区，未涂层铝板表面形成了MgZn 2（η/Zn）相和ZnO相。ZnO相的形成被认为是在循环加载和暴露于空气期间接触未涂覆Al 7075-T6板的表面之间引起的摩擦热的结果。研究了化学镀Ni-P镀层对铝板微动损伤的抑制作用，从而提高了铝板的微动疲劳寿命。结果表明，在Al 7075-T6板上施加Ni-P涂层后，表面粗糙度降低约40%。
This paper aims to characterize the surface damage as a consequence of fretting fatigue in aluminum alloy 7075-T6 plates in double-lap bolted joints through XRD, surface profilometry, and SEM analyses. The main focus was on the surface roughness and chemical phase composition of the damaged zone along with the identification of fretting fatigue crack initiations over the surface of the material. The surface roughness of the fretted zone was found to increase when the joint was clamped with a higher tightening torque and tested under the same cyclic loading. Additionally, MgZn2 (η/ή) precipitates and ZnO phase were found to form onto the surface of uncoated aluminum plate in the fretted and worn zones. The formation of the ZnO phase was understood to be a result of frictional heat induced between the surface of contacting uncoated Al 7075-T6 plates during cyclic loading and exposure to the air. The beneficial role of electroless nickel-phosphorous (Ni–P) coatings in minimizing the fretting damage and thus improving the fretting fatigue life of the aluminum plates was also studied. The results showed that the surface roughness decreased by approximately 40% after applying Ni–P coatings to the Al 7075-T6 plates.