The Effect of Strain Rate on the Hydrogen Embrittlement Susceptibility of Aluminum 7075

Abstract

The effects of changing strain rate regime from quasi-static to medium on hydrogen susceptibility of aluminum (Al) 7075 were investigated by means of tensile tests. Strain rates were selected as 10−3 s−1 and 1 s−1 and tensile tests were conducted on both hydrogen uncharged and hydrogen charged specimens at room temperature. Electrochemical hydrogen charging method was utilized and diffusion length of hydrogen inside Al 7075 was modeled. Material characterizations were carried out by X-ray diffraction (XRD) and energy dispersive X-Ray spectroscopy (EDX) and microstructural observations of hydrogen uncharged and hydrogen charged specimens were performed by scanning electron microscope (SEM). As opposed to previous studies hydrogen embrittlement was more pronounced at high strain rate case. Moreover, hydrogen enhanced localized plasticity was the more dominant hydrogen embrittlement mechanism at slower strain rate but coexistence of hydrogen enhanced localized plasticity and hydrogen enhanced decohesion was observed at a medium strain rate. Overall, the current findings shed light on the complicated hydrogen embrittlement behavior of Al 7075 and constitute an efficient guideline for the usage of Al 7075 that can be subject to different strain rate loadings in service.