亚快速凝固Mg-Zn-Sn-Al-Ca合金的组织、拉伸性能和蠕变性能(英文)  

Microstructure, Tensile Properties and Creep Resistance of Sub-rapidly Solidified Mg-Zn-Sn-AI-Ca Alloys

作　　者：魏菊英[1,2] 陈吉华[1,3] 严红革[1,3] 苏斌[1,3] 张光浩[1,3] 何玺[1,3] 

机构地区：[1]湖南大学,湖南长沙410082 [2]江铃汽车股份有限公司,江西南昌330001 [3]湖南省喷射沉积技术及应用重点实验室,湖南长沙410082

出　　处：《稀有金属材料与工程》2014年第11期2602-2608,共7页Rare Metal Materials and Engineering

基　　金：National Natural Science Foundation of China(51001046,51274092);National Research Foundation for the Doctoral Program of Higher Education of China(20120161110040);Young Teacher Growth Fund of Hunan University(531107021095)

摘　　要：研究了7种亚快速凝固Mg-Zn-Sn-Al-Ca合金的组织、拉伸性能和抗蠕变性能。对于Mg-xZn-ySn-2Al-0.2Ca(x+y=9,x/y为2,1和0.5)合金,锌锡比为1时室温抗拉强度和屈服强度最高:150℃屈服强度随着锌锡比的增加而提高,而200℃相反。这可能与低锌锡比合金中Mg_2Sn较多、含Zn化合物较少且Mg_2Sn具有高温强化作用有关。对于Mg-4.5Zn-4.5Sn-2Al-zCa(z=0,0.2,0.4,0.6)合金,室温和200℃抗拉强度和屈服强度随着Ca含量的增加先提高后下降,峰值分别出现在0.2%Ca和0.4%Ca。200℃/50MPa压缩蠕变时,合金初始应变量和稳态蠕变速率随着Ca含量的增加而降低。少量Ca可以提高Mg-4.5Zn-4.5Sn-2Al合金的室温和高温强度并改善抗蠕变性能,但降低高温塑性。此外,也影响拉伸断裂模式。随着Ca含量的增加,合金室温断裂由解理断裂转变为准解理断裂,200℃断裂由韧性断裂转变为准解理断裂。Microstructures, tensile properties and creep resistances of seven kinds of sub-rapidly solidified Mg-Zn-Sn-AI-Ca alloys were studied. Results show that as for the Mg-xZn-ySn-2Al-0.2Ca （x＋y=9, x/y=2, 1 and 0.5, in mass%） alloys, the highest UTS and YTS at RT are obtained with the Zn/Sn mass ratio of 1. The YTS at 150 ℃ increases but that at 200 ℃ decreases with the increase of Zn/Sn mass ratio. It is possibly ascribed to the elevated-temperature strengthening of Mg2Sn particles since the alloy with the lower Zn/Sn mass ratio contains a higher amount of Mg2Sn and a lower fraction of Zn-containing phases. As for the Mg-4.5Zn-4.5Sn-2Al-zCa （z=0, 0.2, 0.4 and 0.6） alloys, UTS and YTS increase at first and then decrease with the increase of Ca content at both RT and 200 ℃. The strength peaks occur at 0.2% Ca and 0.4% Ca, respectively. Both the initial strain and the steady creep rate decrease with the increase of Ca content below 0.4% Ca at 200 ℃ under the compression stress of 55 MPa. Minor Ca addition can improve the RT and elevated temperature strength and enhance the compressive creep resistance of the Mg-4.5Zn-4.5Sn-2A1 alloy, but reduce the elevated-temperature plasticity. In addition, it also has an obvious influence on the tensile fracture mode, which changes from cleavage to quasi-cleavage at RT and from ductile to quasi-cleavage at 200 ℃ with the increas- ing of Ca addition.

关 键 词：Mg-Zn-Sn合金 CA 显微组织 拉伸性能 蠕变 

分 类 号：TG146.22[一般工业技术—材料科学与工程]