Transition of dynamic recrystallization mechanism during hot deformation of Incoloy 028 alloy

• 来源期刊: 材料科学技术（英文版）
• 年，卷（期）: 2020,（7）
• 页码范围: 241-253
• 页数: 13页
• 语种: 英文

摘要

Dynamic recrystallization (DRX) plays significant roles in manipulating of microstructures during hot deformation and the result mechanical properties;however,the underling mechanism leading to multi scale-microstructures remains poorly understood.Here,the DRX mechanism under wide processing conditions (i.e.950-1200 ℃,0.001-10 s-1) in Incoloy 028 alloy was investigated,where the relationships among flow stress,Z parameter and grain size,as well as the evolution of characteristic microstructures (grain size,sub-grain boundaries,and high angle grain boundaries),are established.As the values of Z parameters decrease (corresponding to decreased flow stresses),three typical softening mechanisms successively occur,ranging from continuous DRX controlled by dislocation glide,discontinuous DRX dominated by dislocation motion (climb and cross/multiple slip) and grain boundary migration,to dynamic normal/abnormal grain growth resulting from grain boundary migration,with transition regions where two adjacent mechanisms occur simultaneously.Correspondingly,these above three softening mechanisms result in ultrafine,fine and coarse grains,respectively.The present findings demonstrate a comprehensive understanding of DRX mechanism over a wide range of processing conditions,and further provide a new guideline for preparing single crystals.