超低温重载工况下陶瓷球失效分析

Failure analysis of two hybrid bearing balls under heavy loads and extremely low temperature conditions

混合轴承陶瓷球在超低温重载条件下工作6 h发生表面局部剥落.为找出失效原因,提高混合陶瓷轴承的寿命和工作可靠性,对发生局部剥落的陶瓷球进行宏观、微观断口显微分析和金相分析.结果表明,发生早期疲劳的陶瓷球与含裂纹陶瓷球滚动接触疲劳试验的失效形式相同.导致实验中陶瓷球失效的原因是陶瓷球表面存在的裂纹扩展,这些裂纹来源于材料中含有较大的夹杂物,并提出了改进措施.

Surface spalling took place on hybrid bearing balls under heavy loads and extremely low temperature conditions in six hours. Fractographic and metallographic analyses were performed to study the potential cause of ceramic ball failure. The same failure mode was found in both the present experiment and rolling contact fatigue experiments on pre-existing surface crack Si3 N4 bearing balls. Failure in this case was caused by propagation of pre-existing surface cracks induced from large inclusions. Material assurance methods and nondestructive inspection must be directly introduced into the manufacturing process to prove mechanical properties of hybrid bearing balls.