Ball screws are widely used in aerospace applications,and the failure mechanisms under conven-tional operating conditions are no longer applicable under extreme aerospace operating conditions.There-fore,for the failure mechanism of ball screw under extreme load,a failure mechanism research method based on crack sprouting and expansion is proposed.The analysis was carried out by electron microscopy,metallography,roughness meter and microhardness.The results indicated that:tangential surface and sub-surface cracks are sprouted perpendicular to the direction of tangential force,surface cracks expand away from the tangential force,and sub-surface cracks expand along the direction of plastic deformation;fatigue cracks generated on the axial surface are at the angle of 50°～85°;the spalling pit morphology is deeper to shallower along the direction of the tangential force,and the area in front of the spalling pit is more suscep-tible to fatigue than that in back of the spalling pit but the area in back of the spalling pit is more suscepti-ble to wear;Foreign ball screw life is higher than domestic,improve ball screw contact surface accuracy and organisation uniformity,it is expected to enhance the service life by 50% .
维普
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