摘要
Hot tearing is known as one of the most serious solidification defects commonly encountered during solidification. It is very important to study the solidification path of alloys. In the work, thermal analysis with cooling curve was used for the investigation of microstructure evolution with different Zn contents during solidification process of MgZn_xY_4Zr_(0.5) alloys. Thermal analysis results of MgY_4Zr_(0.5) alloys revealed one distinct phase precipitation: α-Mg. Three different phase peaks were detected in the Zn-containing alloys: α-Mg, Z-phase(Mg_(12)YZn) and W-phase(Mg_3 Y_2Zn_3). In addition, for the present MgZn_xY_4Zr_(0.5) alloys, the freezing ranges of these alloys from large to small were: MgZn_(1.5)Y_4Zr_(0.5)>MgZn)(3.0) Y)4Zr_(0.5)>MgZn0.5 Y4 Zr0.5>MgY_4Zr_(0.5). The effect of different contents of Zn(0, 0.5, 1.5, 3.0 wt.%) on hot tearing behavior of MgY_4Zr_(0.5) alloy was investigated using a constrained rod casting(CRC) apparatus equipped with a load cell and data acquisition system. The experimental results show that the addition of Zn element significantly increases hot tearing susceptibility(HTS) of the MgY_4Zr_(0.5) alloy due to its extended freezing range. Some free dendrite-like bumps and ruptured liquid films on the fracture surfaces were observed in all the fracture surfaces. These phenomena proved the fact that the hot tearing formation was caused by interdendritic separation due to lack of feeding at the end of solidification.
Hot tearing is known as one of the most serious solidification defects commonly encountered during solidification. It is very important to study the solidification path of alloys. In the work, thermal analysis with cooling curve was used for the investigation of microstructure evolution with different Zn contents during solidification process of MgZnxY4Zr（0.5） alloys. Thermal analysis results of MgY4Zr（0.5） alloys revealed one distinct phase precipitation： α-Mg. Three different phase peaks were detected in the Zn-containing alloys： α-Mg, Z-phase（Mg（12）YZn） and W-phase（Mg3 Y2Zn3）. In addition, for the present MgZnxY4Zr（0.5） alloys, the freezing ranges of these alloys from large to small were： MgZn（1.5）Y4Zr（0.5）〉MgZn）（3.0） Y）4Zr（0.5）〉MgZn0.5 Y4 Zr0.5〉MgY4Zr（0.5）. The effect of different contents of Zn（0, 0.5, 1.5, 3.0 wt.%） on hot tearing behavior of MgY4Zr（0.5） alloy was investigated using a constrained rod casting（CRC） apparatus equipped with a load cell and data acquisition system. The experimental results show that the addition of Zn element significantly increases hot tearing susceptibility（HTS） of the MgY4Zr（0.5） alloy due to its extended freezing range. Some free dendrite-like bumps and ruptured liquid films on the fracture surfaces were observed in all the fracture surfaces. These phenomena proved the fact that the hot tearing formation was caused by interdendritic separation due to lack of feeding at the end of solidification.
基金
financially supported by the National Natural Sciences Foundation of China(No.51504153,No.51571145)
the General Project of Scientific Research of the Education Department of Liaoning Province(No.L2015397)
作者简介
Zhi Wang Female, born in 1983, Doctor. Her research interests mainly focus on high performance magnesium alloys. She has so far published more than 20 papers in national and international journals. E-mail： wangzhi8303@163.com
