ISSN: 1003-6326
CN: 43-1239/TG
CODEN: TNMCEW

Vol. 30    No. 5    May 2020

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Effect of nano-sized Al2O3 reinforcing particles on uniaxial and high cycle fatigue behaviors of hot-forged AZ31B magnesium alloy
M. DAREINI, A. H. JABBARI, M. SEDIGHI
(School of Mechanical Engineering, Iran University of Science and Technology, Narmak, Tehran 1684613114, Iran)
Abstract: The effect of hot-forging process was investigated on microstructural and mechanical properties of AZ31B alloy and AZ31B/1.5vol.%Al2O3 nanocomposite under static and cycling loading. The as-cast alloy and composite were firstly subjected to a homogenization heat treatment at 450 °C and then an open-die forging at 450 °C. The results indicated that the presence of reinforcing particles led to grain refinement and improvement of dynamic recrystallization. The forging process was more effective to eliminate the porosity in the cast alloy workpiece. Microhardness of the forged composite was increased by up to 80% and 16%, in comparison with those of the cast and forged alloy samples, respectively. Ultimate tensile strength and maximum tensile strain of the composite were improved by up to 45% and 23%, compared with those of the forged alloy in similar regions. These enhancements were respectively 50% and 37% in the compression test. The composite exhibited a fatigue life improvement in the region with low applied strain; however, a degradation was observed in the high applied strain region. Unlike AZ31B samples, tensile, compressive and high cycle fatigue behaviors of the composite showed less sensitivity to the applied strain, which can be attributed to the amount of porosity in the samples before and after the hot-forging.
Key words: magnesium matrix nanocomposite; AZ31B alloy; nano-sized Al 2O3; open-die hot-forging; high cycle fatigue; mechanical properties; microstructural evolution
Superintended by The China Association for Science and Technology (CAST)
Sponsored by The Nonferrous Metals Society of China (NFSOC)
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