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Bassiouny Saleh,Jinghua Jiang,Qiong Xu,Reham Fathi,Aibin Ma,Yuhua Li,Lisha Wang 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.8
The main objective of this paper is to study the influence of wear testing parameters on the weight loss of AZ91 magnesiumalloy which was developed via rotary die-equal channel angular pressing (RD-ECAP) method through the different numberof passes. The AZ91 sample was pressed up to 16 passes in order to decrease the grain size to 10 μm. After RD-ECAP processing,significant grain refinement was found, which yielded a refined grain size after 16 passes and enhanced mechanicalproperties and wear resistance. Dry sliding wear experiments with a ball on disc apparatus at room temperature were conducted,following RD-ECAP processing. The response surface methodology (RSM) was used to optimize and compare thewear resistance of the RD-ECAP alloy and the as-received alloy. Analysis of the wear mechanism and the worn surfaces ofAZ91 samples was performed using scanning electron microscope. RSM analysis showed that increased applied load, slidingspeed and sliding time in all cases decreased wear resistance. On the other side, wear resistance in AZ91 magnesium alloywas improved by the increase in the number of passes of RD-ECAP. The three empirical models were validated by conductingconfirmation tests and certified that the proven empirical wear models are reliable for wear applications as a predictive tool.
Lisha Wang,Jinghua Jiang,Bassiouny Saleh,Reham Fathi,He Huang,Huan Liu,Aibin Ma 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.12
This paper optimizes experimental parameters on controlling corrosion performance of the Mg-rare-earth alloys with longperiod stacking ordered structure using response surface methodology. Different NaCl concentrations, temperatures, andvarying pH values are selected as input parameters. The corrosion current density (icorr) and open circuit potential (OCP)are used as the multiple responses to evaluate the corrosion performances. The corrosion surface morphology and corrosionmechanism of the Mg alloys are also investigated by scanning electron microscopy for the optimization. Analysis of variance(ANOVA) has given the impact of individual factors and interactions on the corrosion rate. The results indicated thatthe three test parameters had significant impacts in controlling the corrosion behavior of Mg alloy. Moreover, the increasedNaCl concentration decreased the pitting potential (Epit) of the target materials. Filiform corrosion can be detected in high pHsolutions, whereas the matrix suffered from severe dissolution phenomenon in low pH solutions. High temperature aggravatedthe local destruction and dissolution of the protective film. The interaction of the experimental parameters showed a sizableinfluence on corrosion performance.