LZ50单轴微动疲劳特性研究

Study on uniaxial fretting fatigue properties of LZ50

摘要:

研究了轮轴钢LZ50在单轴微动疲劳条件下的应力-应变滞后回线，微动区的磨损特征及断口和截面形貌；分析讨论了磨屑的形成与演变过程及微动疲劳失效机制。结果表明，LZ50在单轴微动疲劳过程中消耗的塑性不可逆功少，微动损伤机制为粘着磨损、磨粒磨损，并伴有氧化磨损。磨损过程中基体材料脱落、破碎、氧化形成磨屑，其中的硬质氧化物颗粒促进了材料表面的磨粒磨损，加速了疲劳失效过程。微动疲劳裂纹萌生区的宽度大约为100μm，失效断裂面垂直载荷方向。

Abstract:

The uniaxial fretting fatigue characteristics of LZ50 axle steel such as stress-strain hysteresis loop, fretting wear scars, fracture and cross section morphology were investigated. The formation and evolution mechanism of the debris produced in the fretting wear process and the fatigue failure mechanism were analyzed, too. The results indicate that, LZ50, under the condition of uniaxial fretting fatigue loading, had less irreversible plastic power consumption. The fretting fatigue damage mechanisms are adhesive wear and abrasive wear, accompanied with oxidation wear. The fragmentation products wore off from the matrix material surface are oxidized and formed into wear debris, in which the hard particles aggravate the abrasive wear, and accelerated the fretting fatigue failure. The dimension of fretting fatigue crack initiation is about 100μm, and fracture surface is perpendicular to the direction of cyclic loading.