Microstructural evolution and mechanical strengthening mechanism of Mg-3Sn-1Mn-1La alloy after heat treatments
Microstructural evolution and mechanical strengthening mechanism of Mg-3Sn-1Mn-1La alloy after heat treatments
复制标题
Mg-3Sn-1Mn-1La合金热处理后的显微组织演变及力学强化机制
DOI：
10.1016/j.msea.2018.07.083
复制
发表时间：
2018-09-12
期刊：
影响因子：
6.4
通讯作者：
Guo, Zhanhu
中科院分区：
文献类型：
--
作者：
Zhao, Zhanyong;Bai, Peikang;Guo, Zhanhu
采用连续流变轧制法制备了Mg-3Sn-lMn-lLa合金板材，研究了固溶和时效处理对合金组织和力学性能的影响。Mg-3Sn-lMn-lLa合金板材在室温和150℃下的拉伸强度和伸长率随固溶时间的延长而降低。晶粒尺寸逐渐增大。由La5Sn3、Mg2Sn、Mg17La2相和Mg2Sn相组成的片状MgSnLa化合物逐渐消失。同时，晶粒中形成了新的不规则MgSnLa化合物。固溶处理后对合金进行时效处理。随着时效时间的延长，由La5Sn3、Mg2Sn和Mg17La2相组成的新型球状MgSnLa化合物在基体中形成、增加并逐渐均匀分布。同时，在基体中形成球形、短棒状和板条状Mg2Sn相。Mg-3Sn-lMn-lLa合金板材经550℃固溶处理24 h， 250℃时效48 h后，室温和150℃抗拉强度分别提高到270 MPa和233 MPa，分别提高19%和20%。室温和150℃下伸长率分别提高了6%和4%，达到7.9%和67.5%。形成的球状MgSnLa化合物和Mg2Sn相与基体相一致，有效地固定了位错和晶界，提高了合金的力学性能。
The Mg-3Sn-lMn-lLa alloy sheets were prepared by a continuous rheo-rolling process, and the effects of the solution and aging treatment on the microstructures and mechanical properties of the alloy were studied. The tensile strength and elongation at room temperature and 150 degrees C of the Mg-3Sn-lMn-lLa alloy sheets were decreased with increasing the solution time. The grain size was increased gradually. The plate-shaped MgSnLa compounds composed of La5Sn3, Mg2Sn and Mg17La2 phases and Mg2Sn phase gradually disappeared. At the same time, new irregular MgSnLa compounds were formed in grains. Aging treatment of the alloy was performed after solution treatment. The new spherical MgSnLa compounds composed of La5Sn3, Mg2Sn and Mg17La2 phase were formed, increased and distributed gradually homogeneously in the matrix with increasing the aging treatment time. Meanwhile, the Mg2Sn phases with spherical, short-rod and lath-shaped were formed in the matrix. After solution treatment at 550 degrees C for 24 h, aging at 250 degrees C for 48 h, the tensile strength at room temperature and at 150 degrees C of the Mg-3Sn-lMn-lLa alloy sheet was increased to 270 MPa and 233 MPa, with 19% and 20% increase, respectively. The elongation at room temperature and 150 degrees C was increased to 7.9% and 67.5%, with 6% and 4% increase, respectively. The formed spherical MgSnLa compounds and Mg2Sn phases which were coherent with the matrix and effectively pinned the dislocations and grain boundaries were responsible for the enhanced mechanical properties of the alloys.