논문 상세보기
pp.45-54
This study investigated the hot deformation behavior and microstructural evolution of PH13-8Mo precipitation-hardening stainless steel. Hot compression tests were performed at temperatures ranging from 900 to 1,200 °C and strain rates of 0.01 to 10 s-1. Constitutive equations based on the Zener-Hollomon parameter were established by considering the compensation of strain, where the material constants were fitted with 6th-order polynomials. The established model showed high predictability with a correlation coefficient of 0.994 and an average absolute relative error of 4.39 %. A hot processing map was developed based on the Dynamic Materials Model, identifying unstable regions characterized by negative instability criteria under low-temperature/high-strain-rate conditions, as well as specific moderate-rate zones. Electron backscatter diffraction (EBSD) integrated analysis [inverse pole figure (IPF), kernel average misorientation (KAM), and grain orientation spread (GOS)] revealed that while dynamic recrystallization promoted grain refinement through necklace structures at 900 °C and 0.01 s-1, high-temperature deformation at 1,200 °C led to significant grain coarsening and high transformation-induced stress. Furthermore, regions of instability were confirmed to cause flow localization and strain hotspots, detrimental to structural integrity. Consequently, the moderate temperature region around 1,100 °C with a low strain rate is proposed as the optimal window for achieving uniform and stable prior austenite grain structures.
1. 서 론
2. 실험 방법
3. 결과 및 고찰
3.1. 마찰 보정 유동응력 곡선
3.2. 구성 방정식
3.3. 공정 지도
3.4. 미세 조직 진화
4. 결 론
Acknowledgement
References
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