高碳高合金马氏体钢回火过程连续性转变的内耗行为研究

Internal Friction Behavior of Continuous Transformation During the Process of Tempering on the High Carbon High Alloyed Martensitic Steel

高碳高合金马氏体钢淬火后在回火过程中存在过饱和碳原子偏聚现象,碳原子偏聚于位错附近的间隙位置,回火过程中以碳化物形式沉淀析出。通过内耗研究表明,随着回火温度的增加,Snoek峰驰豫强度下降并消失,SKK峰驰豫强度降低并随回火温度的升高而宽化。由该结果可知由于大量碳原子偏聚于位错处,随后以细颗粒碳化物形式在位错处析出。随着回火温度增加,大部分位错回复消失及碳化物聚集长大,同时残余奥氏体分解产生硬化效应,使钢的硬度增加而韧性下降。

The supersaturating carbon atoms were apt to segregate nearby the dislocations and precipitated as carbides in the high carbon high alloy martensitic steels during tempering.The results of internal friction behavior show that the strength of Snoek relaxation and the SKK peak are reduced with the incensement of tempering temperature.In addition,the SKK peaks are broader while the temperature increases.The results indicate the carbon atoms clusters nearby the dislocations and precipitated as carbides during tempering.The dislocations are eliminated and the carbides grow up in the process of tempering.At the same time,the transformation of retained austenite enhances the hardness and decreases the toughness.