Transactions of Nonferrous Metals Society of China The Chinese Journal of Nonferrous Metals

您目前所在的位置:首页 - 期刊简介 - 详细页面

中国有色金属学报

ZHONGGUO YOUSEJINSHU XUEBAO

第27卷    第10期    总第223期    2017年10月

[PDF全文下载]        [Flash在线阅读]

    

文章编号:1004-0609(2017)-10-1970-11
钇含量对MgZn4.5YxZr0.5合金热裂敏感性的影响
冯 羽,毛萍莉,刘 正,王 志,张斯博,王 峰

(沈阳工业大学 材料科学与工程学院,沈阳 110870)

摘 要: 采用热分析法和铸造热裂试验研究MgZn4.5YxZr0.5(x=0.5,1,2,4,6(质量分数, %))合金的热裂行为。结果表明:MgZn4.5Y1Zr0.5合金的枝晶干涉温度Tcoh最高、在脆弱区域的温度差ΔTc最大、在最后凝固阶段剩余的液相量最少、形成的液膜厚度较薄,补缩程度较低,所能抵御的凝固收缩力最小、裂纹扩展速率最大。这些现象说明MgZn4.5Y1Zr0.5合金具有最高的热裂敏感性。随着Y含量的增加,聚集在晶界处的低熔点相对合金热裂行为的作用以及合金的热裂形成机制均发生变化:当Y含量不超过1%时,低熔点相主要对晶间结合力起破坏作用,合金的热裂形成机制主要是晶间搭桥的断裂;当Y含量超过1%时,低熔点相主要对枝晶分离区起补缩作用,合金的热裂形成机制为晶间搭桥、枝晶分离区域的补缩和液膜共同作用。

 

关键字: Mg-Zn-Y-Zr系合金;凝固参数;热裂敏感性

Effect of yttrium content on hot tearing susceptibility of MgZn4.5YxZr0.5 alloys
FENG Yu, MAO Ping-li, LIU Zheng, WANG Zhi, ZHANG Si-bo, WAMG Feng

School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110870, China

Abstract:Thermal analysis method and constrained rod casting (CRC) were used to study hot tearing behavior of MgZn4.5YxZr0.5 (x=0.5, 1, 2, 4, 6 (mass fraction, %)) alloys. The results show that MgZn4.5Y1Zr0.5 alloy possesses the highest hot tearing susceptibility (HTS) among the tested alloys due to the highest coherency temperature (Tcoh), the largest temperature difference (ΔTc) in vulnerable region, the least residual liquid in last stage of solidification, the lowest anti-contraction force of thinner film, the poorer feeding capability and the highest crack propagation rate. The role of low-melting point phases gathering at grain boundary on the HTS and the main mechanism of hot tearing shift gradually with different Y contents: when Y is not more than 1%, the role is mainly a damaging effect on intergranular binding force and the main mechanism is fracture of intergranular bridges; when Y is more than 1%, the role is mainly an intergranular feeding effect on formed separated dendrites and the main mechanism is the collective effect of intergranular bridges, intergranular feeding and film.

 

Key words: Mg-Zn-Y-Zr alloy; solidification parameter; hot tearing susceptibility

ISSN 1004-0609
CN 43-1238/TG
CODEN: ZYJXFK

ISSN 1003-6326
CN 43-1239/TG
CODEN: TNMCEW

主管:中国科学技术协会 主办:中国有色金属学会 承办:中南大学
湘ICP备09001153号 版权所有:《中国有色金属学报》编辑部
------------------------------------------------------------------------------------------
地 址:湖南省长沙市岳麓山中南大学内 邮编:410083
电 话:0731-88876765,88877197,88830410   传真:0731-88877197   电子邮箱:f_ysxb@163.com