中文摘要：

以工艺强化后某轿车等速万向传动中间轴材料试样的扭转断裂为对象，试验研究了不同载荷强化和损伤后试样的静扭转断裂和疲劳扭转断裂断口形貌、断口硬度特性以及剩余静强度、剩余静刚度和断口硬度之间的相互关系和变化规律。研究结果表明，无论是经过小载荷强化还是疲劳大载荷损伤的材料试样，其静扭转断裂断口都是横向剪切断裂且断口十分平齐；材料试样无论是否经历强化或损伤，其疲劳断裂断口呈现正断或横向切断不平齐两种形貌，正断和横向切断不平齐两种疲劳断口形貌与试样的强化过程、损伤过程以及试样的疲劳寿命之间没有明显的内在关系；疲劳过程中试样的剩余静强度、剩余静刚度和断口平均硬度的变化趋势和规律基本一致。

英文摘要：

Using the material specimen of a constant velocity universal drive shaft processed with strengthening technology as a test object,the form and type of torsional fracture,the hardness characteristic of fracture and the relationships among fracture hardness,residual static strength and residual static stiffness were investigated.The results show that the static fracture morphology is of smooth transverse shear whether the strengthening by light load or the damaging by heavy load has been carried out on the specimen under the action of fatigue load spectrum.All the morphologyies of fatigue fracture are of rugged transverse shear or tensile fracture,and they bear no obvious internal relations to the strengthening process,damage process and fatigue life.During the process of specimen fatigue frature,the residual static strength,residual static stiffness and average hardness of fracture area retain the same chamging trend and rule.