Effects of Filtration Purification and Solution Treatment on the Microstructure and Mechanical Property of AZ91D Alloy

Abstract:

As-cast and solution-treated microstructures of AZ91D alloy before and after the purification by MgO ceramic foam filter (CFF) with different thicknesses at the range from 15 mm to 35 mm were investigated by optical microscopy and scanning electron microscopy. Meanwhile, the tensile mechanical property and impact toughness were tested. The results show that the impurities in the alloy melt could be eliminated by the filtration purification effectively. With increasing the thickness of CFF, the tensile mechanical property and impact toughness first increased significantly, and then decreased slightly. The AZ91D alloy purified by the CFF with the thickness of 20 mm and the porosity of 10 ppi exhibited the best comprehensive mechanical property. The tensile strength σ_b, elongation δ and impact toughness α_nK at ambient temperature reached 205 MPa, 8.5% and 16 J/cm², with the improving amplitude of 13%, 31% and 46% comparing with the corresponding unpurified value, respectively. At the same time, σ_b and δ at elevated temperature reached 195 MPa and 31.5%, with the improving amplitude of 9% and 174%, respectively. After the alloy was solution treated, the mechanical property was enhanced further, and the improving amplitude was larger for the alloy by the filtration purification. σ_b reached 260 MPa and 205 MPa at ambient and elevated temperatures, with the improving amplitude of 32% and 5% comparing with the unpurified value, respectively. α_nK reached 27 J/cm², with the improving amplitude of 69%.

• Periodical: Materials Science Forum (Volume 849)
• Pages: 134-141
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.849.134
• Online since: March 2016
• Authors: Wang Han Bo Liu, Wen Jun Qi*, Zheng Hua Huang
• Keywords: AZ91D Alloy, Ceramic Foam Filter, Filtration Purification, Impact Toughness, Tensile Mechanical Property

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