The effect of different heat treatment processes on the microstructure and mechanical properties of the as-cast Mg-5Sm-0.6Zn-0.5Zr alloy was investigated by orthogonal test. The results show that the as-cast Mg-5Sm-0.6Zn-0.5Zr alloy mainly consists of magnesium matrix (α-Mg) and eutectic second-phase; the order of influence of each factor on the average grain size is:solution time > aging temperature > aging time; the effect order of each factor on the tensile strength of the alloy is:aging temperature > solution time > aging time; the influence order of each factor on the elongation of the alloy after fracture is:solution time > aging temperature > aging time. The optimum heat treatment process with good comprehensive mechanical properties is as follows:the solution temperature is 540℃, the solution time is 12h, the aging temperature is 200℃, the aging time is 10h. The analysis of fracture morphology shows that the fracture mode of the as-cast alloy is quasi-cleavage fracture; the fracture modes of the aged alloys are complex, including quasi-cleavage fracture, cleavage fracture and intergranular fracture.
XU H X , ZHANG X L . Green enviroment-friendly materials for 21 century-magnesium alloys[J]. Journal of Shanghai University of Engineering Science, 2007, 21 (4): 322- 325.
ZHANG J H , TANG D X , ZHANG H J , et al. Effect and application of rare earth element in magnesium alloys[J]. Chinese Journal of Rare Metals, 2008, 32 (5): 659- 667.
ZHANG H J , MENG J , TANG D X . Investigation, exploitation and application of magnesium-rare earth alloy as a structure material[J]. Journal of the Chinese Society of Rare Earths, 2004, 22 (1): 40- 47.
PENG J , PENG Y , HAN W , et al. Effect of extruded temperature on microstructure and mechanical properties of Mg-2Zn-Mn-0.5Nd alloy[J]. Journal of Materials Engineering, 2015, 43 (3): 23- 27.
YAN J J , SUN Y S , XUE F , et al. Creep behavior of Mg-2wt.%Nd binary alloy[J]. Materials Science and Engineering:A, 2009, 524 (1/2): 102- 107.
WANG S R , MA R , YANG L Y , et al. Precipitates effect on microstructure of as-deformed and as-annealed AZ41 magnesium alloys by adding Mn and Ca[J]. Journal of Materials Science, 2011, 46 (9): 3060- 3065.
ZHANG K , MA M L , LI X G , et al. Hot deformation behavior of Mg-7.22Gd-4.84Y-1.26Nd-0.58Zr magnesium alloy[J]. Rare Metals, 2011, 30 (1): 87- 93.
YANG M B , PAN F S , SHEN J , et al. Comparison about as-cast microstructures and mechanical properties of Mg-4Y-1.2Mn-1Zn(wt%) magnesium alloys[J]. Journal of Materials Science, 2011, 46 (9): 3094- 3100.
曾小勤. 稀土镁合金研究与应用进展[J]. 稀土信息, 2016, (2): 26- 29.
ZENG X Q . Research and application of rare earth magnesium alloys[J]. Rare Earth Information, 2016, (2): 26- 29.
SON H T , LEE J S , KIM D G , et al. Effects of samarium (Sm) additions on the microstructure and mechanical properties of as-cast and hot-extruded Mg-5wt% Al-3wt% Ca-based alloys[J]. Journal of Alloys and Compounds, 2009, 473 (1/2): 446- 452.
MIAO X W , PENG K X , ZHANG J Y , et al. Effect of solution and aging treatment on microstructure and thermal conductivity of Mg-2.5Nd-1.0Zn-0.5Zr alloy[J]. Shanghai Metals, 2013, 35 (6): 1- 5.