奥氏体不锈钢的低温循环硬化

本文对奥氏体不锈钢1Cr18Ni9Ti进行了应变疲劳试验，研究了循环变形过程中的微观结构变化以及循环硬化机理。1Cr18Ni9Ti在室温和低温下均发生循环硬化。经室温和低温应变疲劳可形成α′马氏体和ε马氏体，ε马氏体极少，α′马氏体形貌为板条状和短快状。1Cr18Ni9Ti循环硬化机制为，随循环周次增加，α′马氏体的不断形成使得材料发生硬化，当新形成的马氏体造成的硬化和先形成的马氏体在随后的循环中发生的软化达到动态平衡时，即达到了循环硬化饱和状态。

CYCLIC HARDENING MECHANISM OF AUSTENITIC STAINLESS STEEL 1Cr18Ni9Ti AT LOW TEMPERATURE

The low cycle fatigue test of austenitic stainless steel 1Cr18Ni9Ti has been conducted at room and low temperature in this paper. Cyclic hardening mechanism and microstructure changes during strain cycling have been studied. Cyclic hardening was observed at room and low temperature. Ε and α′ marten site can be formed by strain cycling in the austenitic stainless steel 1Cr18Ni9Ti at room and low temperature. The content of ε marten site is less than 1.5% and the α′marten site is plate-like and blocky. The mechanism of cyclic hardening of 1Cr18Ni9Ti steel is the following. Cyclic hardening results mainly from the formation of marten site during strain cycling. When the balance between the hardening resulting from newly formed marten site and the softening of marten site formed early is established, the cyclic hardening saturation is reached.