ABSTRACT

In this study, the flow behaviour, and microstructure evolution of the SDSS2507 were systematically investigated via hot compressive tests. Subsequently, the hot processing map was constructed according to the obtained stress–strain curves and corresponding equations. Additionally, metallographic examinations of hot compressed specimens found that the softening mechanism of the ferrite and austenite is dynamic recovery (DRV) and dynamic recrystallisation (DRX), respectively. With increasing the strain rate, it promotes the DRX in austenite. Moreover, micro-cracks could initiate from the ferrite/austenite phase boundaries or grain boundaries within the ferrite due to the strong discrepancy of deformation coordination between the two phases or precipitation of Cr₂N precipitates along the ferrite/austenite phase boundaries or ferrite grains at higher strain rate. Considering the hot processing map and microstructural evolution in SDSS2507, the optimum hot processing parameters for SDSS2507 are found to be in a low strain rate range of 0.1–3 s⁻¹ with the temperature range of above 950°C.

摘要

在这项研究中，通过热压试验系统地研究了 SDSS2507 的流动行为和微观结构演变。随后，根据获得的应力-应变曲线和相应的方程构建热加工图。此外，热压缩试样的金相检验发现，铁素体和奥氏体的软化机制分别是动态回复 (DRV) 和动态再结晶 (DRX)。随着应变速率的增加，它促进了奥氏体中的 DRX。_{此外，由于两相之间变形协调的强烈差异或 Cr 2}的析出，微裂纹可能从铁素体/奥氏体相界或铁素体内部的晶界开始N 在较高应变速率下沿铁素体/奥氏体相界或铁素体晶粒析出。考虑到 SDSS2507 的热加工图和微观结构演变，发现 SDSS2507 的最佳热加工参数在 0.1–3 s ^-1的低应变率范围内，温度范围高于 950°C。