耐磨钢中Ti的析出行为及其对冲击磨损性能的影响

Precipitation behavior of Ti in wear resistant steel and its effect on impact wear properties

研究了不同Ti含量(0.03 mass%和0.15 mass%)的耐磨钢中Ti的析出行为及其对冲击磨损性能的影响。结果表明:低Ti含量钢中的大尺寸析出相占比明显低于高Ti含量钢;亚微米级/微米级(Ti,Mo)N析出相在温度较高的液相或者液/固两相区析出,多呈尖锐棱角的不规则多边形或矩形;纳米级(Ti,Mo)(C,N)析出相在温度较低的固相区析出,多为细小的近球状。低Ti含量钢的冲击磨损性能优于高Ti含量钢,亚微米级/微米级(Ti,Mo)N析出相使材料断裂的临界应变能降低,基体和析出相分离所需的应力下降,容易产生微裂纹,导致在冲击磨损过程产生大量犁削;纳米级(Ti,Mo)(C,N)析出相使基体的应变能低于裂纹扩展所需要的界面能,能够阻止在冲击磨损过程中产生的切削,使得耐磨性增加。

The precipitation behavior of Ti in wear resistant steels with different Ti contents(0.03 mass%and 0.15 mass%)and its effect on impact wear properties were studied.The results show that the proportion of large-sized precipitates in low Ti content steel is obviously lower than that in high Ti content steel.Submicron/micron-scale(Ti,Mo)N precipitates are precipitated in the liquid phase or liquid/solid two-phase region with higher temperature,and most of them are irregular polygons or rectangles with sharp edges and corners.Nano-scale(Ti,Mo)(C,N)precipitates are precipitated in the solid phase region with low temperature,and most of them are fine and nearly spherical.The impact wear performance of the steel with low Ti content is better than that of the steel with high Ti content.The submicron/micron-scale(Ti,Mo)N precipitates reduce the critical strain energy of material fracture,resulting in the decrease of the stress required for the separation of the matrix and the precipitates,which will facilitate the production of micro-cracks,and cause a large number of ploughing in the impact wear process.The nano-scale(Ti,Mo)(C,N)precipitates make the strain energy of the matrix lower than the interface energy required for crack propagation,which can prevent cutting production during impact wear and increase the wear resistance of the matrix material.