Age hardening characteristics and mechanical properties of Mg-3.5Dy-4.0Gd-3.1Nd-0.4Zr alloy
(1.上海市上海交通大学轻合金精密成型国家工程中心
2.National Engineering Research Center for Light Alloy Net Forming, Shanghai Jiao Tong University,Shanghai 200030, China)
2.National Engineering Research Center for Light Alloy Net Forming, Shanghai Jiao Tong University,Shanghai 200030, China)
Abstract: Age hardening characteristic and tensile property of Mg-3.5Dy-4.0Gd-3.1Nd-0.4Zr alloy were investigated. The alloy exhibits a considerable age hardening effect up to 250 ℃. Increasing the aging temperature leads to a shorter aging time to reach the peak hardness and a lower peak hardness. The tensile results show that the peak-aged specimens have higher tensile strength at the temperature below 200℃. However, with the increase of temperature further, the tensile strength decreases dramatically and elongation increases drastically. The loss in tensile strength and increase in elongation at high temperature are possibly associated with the instability of secondary precipitates. The fracture mechanism of alloy transfers from intergranular to transgranular with the increase of experimental temperature.
Key words: Mg-Dy-Gd-Nd alloy; heavy rare-earth; aging characteristics; high temperature tensile; microstructure