贝氏体钢在多次冲击接触载荷下的反常磨损行为研究

Abnormal Wear Behavior of Bainite Steel under Multiple Impact Loads

采用JD-125型冲击试验机对贝氏体钢表面进行40 h的往复冲击磨损试验,观察表层组织演变和磨损率的变化过程.结果表明:在6.0 J冲击下磨损率始终稳定不变,呈现出通常的冲击磨损规律;而在8.2 J冲击下,冲击10 h后磨损率急剧下降,甚至低于6.0 J冲击下的磨损率,材料显示出反常的磨损规律;8.2 J冲击下材料磨损表面出现大量非晶相,且出现少量纳米晶嵌于非晶基底中,使得普通的冲击磨损过程被强烈抑制,因此磨损率下降,其磨损表面形貌也较低能冲击下的表面更为平整和均匀.同时还证明只有冲击能量超过某个阈值,材料表面才能够形成非晶层.

Using JD-125 reciprocating impact wear tester, the surface of Bainite steel is separately impacted for 40 h to observe evolution of microstructure in surface and changes of wear rate. When the impacting energy is 6 J, the wear rate kept invariability all the time, which shows an usual wear rule ; When the impacting energy is 8.0 J, the wear rate sharply decreased after impacted 10 h and was lower than that of 6.0 J, an abnormal wear phenomenon occurred. With the help of HRTEM, a lot of amorphous phase was found in surface and some nanocrystalline embed in the amorphous basis. Because of the appearance of amorphous layer, usual wear mechanism was restrained strongly and its wear rate decreased, its surface topography is more even and smooth than that of 6.0 J. Result indicates that the amorphous layer can form only when the impact energy exceeds a certain threshold.