32Mn-7Cr-0.6Mo-0.3N奥氏体钢低温变形与断裂的特征

Cryogenic Deformation and Fracture Characteristic of 32Mn-7Cr-0.6Mo-0.3N Austenitic Steel

测定了32Mn－7Cr－0．6Mo－0．3N奥氏体钢77K温度下的力学性能、组织稳定性，并研究了其低温变形和断裂行为。结果表明：该钢具有很好的低温强度和韧性以及高的组织稳定性。由于氮原子的影响以及在低温变形过程中产生的滑移带、形变李晶、位错间的相互作用，导致该钢具有较高的加工硬化率和高的均匀延伸率。该钢于77K发生沿（111）历发生穿晶断裂，沿晶断裂被完全抑制。77K断口为韧窝占主导并混有少量准解理小刻面的韧性断裂特征。

The mechanic properties, stability of phase, behaviorof cryogenic deformation and fracture of 32Mn-7Cr0. 6Mo-0. 3Naustenitic steel at 77K were investigated. The results show thatthis steel has satisfied cryogenic strength and toughness, highstability of phase. The effects of Nitrogen atoms and the inter-action among slip-bands, deformation twins and dislocationsformed during cryogenic deformation result in high work-hardening rate and homogeneous elongation. The cryogenicintergranular fracture is fully restricted. The transgranular frac-ture occurs along {111}r planes. The fracture sndce at 77Kmainly consists of large quantity of dimples and a little of smallquasi-cleavage facets.