Cheng Weili, Tian Liang, Ma Shichao, Bai Yang, Wang Hongxia
School of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024, China.
Shanxi Key Laboratory of Advanced Magnesium-Based Materials, Taiyuan University of Technology, Taiyuan 030024, China.
Materials (Basel). 2017 Jun 27;10(7):708. doi: 10.3390/ma10070708.
An I-phase containing Mg-8Sn-6Zn-2Al (wt %; TZA862) alloy was fabricated and subjected to different number of passes of equal channel angular pressing (ECAP) processing at 300 °C. The results showed that the alloys exhibited a bimodal microstructure, which consisted of fine dynamically recrystallized (DRX) grains and coarse non-DRX grains. When increasing the number of ECAP passes from 2 to 6, the fraction of DRX grains and the dispersed second phase particles subsequently increase. However, the fraction and particles then decrease once the number of ECAP passes increases to 8. After 6 ECAP passes, remarkable grain refinement was achieved and increasing the number of passes to 8 cannot further refine the microstructure. Furthermore, the alloys having undergone ECAP exhibited a strong ED-tilted texture, the intensity of which increased with an increase in the number of ECAP passes. The ultimate tensile strength (UTS; 338 MPa) and elongation (El.; 14.2%) of the alloy processed with 6 ECAP passes were considerably higher compared to those of the other materials that had undergone ECAP. These significant enhancements were attributed to extensive grain boundary strengthening, precipitation strengthening and a higher work-hardening capacity.
制备了一种含Mg-8Sn-6Zn-2Al（重量百分比；TZA862）的I相合金，并在300℃下进行了不同道次的等径角挤压（ECAP）加工。结果表明，该合金呈现出双峰微观结构，由细小的动态再结晶（DRX）晶粒和粗大的非DRX晶粒组成。当ECAP道次从2增加到6时，DRX晶粒的比例和弥散的第二相粒子随后增加。然而，一旦ECAP道次增加到8，比例和粒子数量就会减少。经过6道次ECAP后，实现了显著的晶粒细化，将道次增加到8并不能进一步细化微观结构。此外，经过ECAP处理的合金呈现出强烈的ED倾斜织构，其强度随着ECAP道次的增加而增加。与经过ECAP处理的其他材料相比，经过6道次ECAP处理的合金的极限抗拉强度（UTS；338MPa）和伸长率（El.；14.2%）显著更高。这些显著的增强归因于广泛的晶界强化、析出强化和更高的加工硬化能力。
