Microstructure and elevated-temperature tensile properties of differential pressure sand cast Mg-4Y-3Nd-0.5Zr alloy

• Published in: China foundry Vol. 13; no. 1; pp. 30 - 35
• Main Authors: Liu, Hong-hui, Ning, Zhi-liang, Sun, Hai-chao, Cao, Fu-yang, Wang, Hao, Zhao, Xin-yi, Sun, Jian-fei
• Format: Journal Article
• Language: English
• Published: Singapore Springer Singapore 2016; Foundry Journal Agency; National Key Laboratory for Precision Hot Processing of Metals, Harbin Institute of Technology, Harbin 150001, China; School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China; Harbin Dongan Engine(Group)Co.Ltd., Harbin 150066, China%School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China
• Subjects: Alloys; Electron microscopy; Engineering; fracture; Grain boundaries; Machines; Manufacturing; Materials Engineering; Mechanical properties; mechanical property at elevated temperature; Metallic Materials; Mg-4Y-3Nd-0.5; Microscopy; microstructure; Processes; Research & Development; Specialty metals industry; Zirconium; Zr alloy; mechanical property at elevated temperature; microstructure; Mg-4Y-3Nd-0.5Zr alloy; TG146.22; fracture
• ISSN: 1672-6421; 2365-9459; 1672-6421
• DOI: 10.1007/s41230-016-5014-1

The microstructures of an Mg-4Y-3Nd-0.5Zr alloy by differential pressure casting were investigated using scanning electron microscopy （SEM） and transmission electron microscopy （TEM）, and its tensile deformation behavior was measured using a Gleeble1500D themo-simulation machine in the temperature range of 200 to 400 ℃ at initial strain rates of 5×10^-4 to 10^-1 s^-1. Results show that the as-cast microstructure consists of primary α-Mg phase and bone-shaped Mg5RE eutectic phase distributed along the grain boundary. The eutectic phase is dissolved into the matrix after solution treatment and subsequently precipitates during peak aging. Tensile deformation tests show that the strain rate has little effect on stress under 300 ℃. Tensile stress decreases with an increase in temperature and the higher strain rate leads to an increase in stress above 300 ℃. The fracture mechanism exhibits a mixed quasi-cleavage fracture at 200 ℃, while the fracture above 300 ℃ is a ductile fracture. The dimples are melted at 400 ℃ with the lowest strain rate of 10^-4 s^-1.