Flow behavior and dynamic softening mechanism of Pt-10Ir precious alloy
(1. Materials Genome Institute, School of Materials and Energy, Yunnan University, Kunming 650091, China;
2. Kunming Precious Materials & Technology Co., Ltd., Yunnan Precious Metals Laboratory Co. Ltd., Sino-Platinum Metals Co. Ltd., Kunming 650106, China;
3. Kunming Institute of Precious Metals, Kunming 650106, China;
4. State Key Laboratory of Advanced Technologies for Comprehensive Utilization of Platinum Metals, Sino-Platinum Metals Co., Ltd., Kunming 650106, China;
5. Shaanxi Key Laboratory of Biomedical Metal Materials, Northwest Institute for Non-ferrous Metal Research, Xi’an 710016, China;
6. College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China)
2. Kunming Precious Materials & Technology Co., Ltd., Yunnan Precious Metals Laboratory Co. Ltd., Sino-Platinum Metals Co. Ltd., Kunming 650106, China;
3. Kunming Institute of Precious Metals, Kunming 650106, China;
4. State Key Laboratory of Advanced Technologies for Comprehensive Utilization of Platinum Metals, Sino-Platinum Metals Co., Ltd., Kunming 650106, China;
5. Shaanxi Key Laboratory of Biomedical Metal Materials, Northwest Institute for Non-ferrous Metal Research, Xi’an 710016, China;
6. College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China)
Abstract: The hot deformation behavior of Pt-10Ir alloy was studied under a wide range of deformation parameters. At a low deformation temperature (950-1150 °C), the softening mechanism is primarily dynamic recovery. In addition, dynamic recrystallization by progressive lattice rotation near grain boundaries (DRX by LRGBs) and microshear bands assisted dynamic recrystallization (MSBs assisted DRX) coordinate the deformation. However, it is difficult for the dynamic softening to offset the stain hardening due to a limited amount of DRXed grains. At a high deformation temperature (1250-1350 °C), three main DRX mechanisms associated with strain rates occur: DRX by LRGBs, DRX by a homogeneous increase in misorientation (HIM) and geometric DRX (GDRX). With increasing strain, DRX by LRGBs is enhanced gradually under high strain rates; the “pinch-off” effect is enhanced at low strain rates, which was conducive to the formation of a uniform and fine microstructure.
Key words: platinum alloy; hot deformation; microstructure evolution; dynamic recovery; dynamic recrystallization