Enhanced strengthening by two-step progressive solution and aging treatment in AM50−4%(Zn,Y) magnesium alloy

• Published in: Transactions of Nonferrous Metals Society of China Vol. 28; no. 12; pp. 2419 - 2426
• Main Authors: DAI, Shuai, WANG, Feng, MA, De-zhi, WANG, Zhi, LIU, Zheng, MAO, Ping-li
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.12.2018
• Subjects: aging treatment; AM50−4%(Zn,Y) alloy; microstructure; solution; strengthening mechanism; thermal analysis; strengthening mechanism; AM50−4%(Zn,Y) alloy; aging treatment; microstructure; solution; thermal analysis
• ISSN: 1003-6326
• DOI: 10.1016/S1003-6326(18)64888-5

AM50−4%(Zn,Y) alloy with a Zn/Y mole ratio of 6:1 was subjected to thermal analysis, and the results were used for designing a two-step progressive solution treatment process. The effects of solution and aging treatments on the microstructure and mechanical properties of the AM50−4%(Zn,Y) alloy were investigated using OM, XRD, SEM/EDS, TEM, tensile test and hardness test. The experimental results demonstrated that the two-step progressive solution treatment could make the Φ and β phases sufficiently dissolve into the matrix which possessed higher supersaturated degree of the dissolved solute compared with the one-step solution treatment. This resulted in a certain enhancement of the precipitation strengthening effect during the subsequent aging process. The precipitation of the Ф phase had a greater impact on the comprehensive mechanical properties of the alloy than β phase precipitation when the aging treatment was performed at 180 °C. The peak aging strength of the AM50−4%(Zn,Y) alloy which was subjected to the two-step progressive solution treatment process (345 °C for 16 h and 375 °C for 6 h) was obtained after the aging treatment at 180 °C for 12 h.