Effect of aging temperature on microstructure and mechanical properties of Mg-12Gd-3Y-1Sm-0.5Zr alloy
San-ling FU1, Quan-an LI2,3(), Qing ZHANG2
1 School of Physics and Engineering, Henan University of Science and Technology, Luoyang 471023, Henan, China 2 School of Materials Science and Engineering, Henan University of Science and Technology, Luoyang 471023, Henan, China 3 Collaborative Innovation Center of Nonferrous Metals, Henan Province, Luoyang 471023, Henan, China
Mg-12Gd-3Y-1Sm-0.5Zr alloy was prepared by induction melting, and the microstructure and properties of the alloy after heat treatment at different aging temperatures were analyzed by X-ray diffraction(XRD), optical microscope(OM), transmission electron microscopy(TEM), micro-hardness and tensile test. The results show that the alloy grain size gradually increases with the increase of aging temperature, the number of the second phase in the grain increases, and the time during which the hardness peak appears gradually decreases when Mg-12Gd-3Y-1Sm-0.5Zr alloy is peak aged at 200, 250 ℃ and 300 ℃. The precipitated phase is β' when the aging temperature is 200 ℃ and 250 ℃, and the precipitated phase is β phase when the aging temperature is 300 ℃. The mechanical properties of the alloy peak aged at 250 ℃ are the best. In the process of stretching at room temperature, 200, 250 ℃ and 300 ℃, the tensile strength of the aging peak alloy at 200 ℃ and 250 ℃ shows the abnormal temperature effect of increasing at first and then decreasing, but while no such abnormal phenomenon appears in the alloy after peak aging heat treatment at 300 ℃.
WU G H , CHEN Y S , DING W J . Current research, application and future prospect of magnesium alloys in aerospace industry[J]. Manned Spaceflight, 2016, 22 (3): 281- 292.
WANG Z J , ZHANG C P , SHAO X H , et al. Effects of Er addition in flux on microstructure and properties of casting AZ91 magnesium alloy[J]. The Chinese Journal of Nonferrous Metals, 2007, 17 (2): 181- 187.
LIU W C , DONG J , SONG X , et al. Effect of microstructures and texture development on tensile properties of Mg-10Gd-3Y alloy[J]. Materials Science and Engineering: A, 2011, 528 (6): 2250- 2258.
HUANG Z H , QI W J , XU J , et al. Microstructures and mechanical properties of Mg-Al-Sm series heat-resistant magnesium alloys[J]. Transactions of Nonferrous Metals Society of China, 2015, 25 (1): 22- 29.
XU G L , YUAN X L , LIU L B . Microstructure and mechanical property of Mg-Al-Zn-Sm alloy and its thermodynamic analysis[J]. The Chinese Journal of Nonferrous Metals, 2012, 22 (5): 1255- 1261.
TONG G D , LIU H F , LIU Y H . Effect of rare earth additions on microstructure and mechanical properties of AZ91 magnesium alloys[J]. Transactions of Nonferrous Metals Society of China, 2010, 20 (Suppl 2): 336- 340.
XU Y D , HU S S , LI S , et al. Influence of heat treatment on the microstructure and property of Mg-Nd-Gd-Zn-Zr alloy[J]. Rare Metal Materials and Engineering, 2011, 40 (7): 1133- 1137.
CHEN X H , HUANG X W , PAN F S , et al. Effects of heat treatment on microstructure and mechanical properties of ZK60 Mg alloy[J]. Transactions of Nonferrous Metals Society of China, 2011, 21 (4): 754- 760.
ZHAO J , LI J P , GUO Y C , et al. Calphad and experimental study on the new type Mg-Gd-Y phase diagram in the Mg-Rich region[J]. Rare Metal Materials and Engineering, 2008, 37 (2): 281- 285.
ZHENG J X , XU X S , ZHANG K Y , et al. Novel structures observed in Mg-Gd-Y-Zr during isothermal ageing by atomic-scale HAADF-STEM[J]. Materials Letters, 2015, 152, 287- 289.
GAO Y , WANG Q D , GU J H , et al. Behavior of Mg-15Gd-5Y-0.5Zr alloy during solution heat treatment from 500 to 540℃[J]. Materials Science and Engineering: A, 2007, 459 (1/2): 117- 123.