高强铝合金的表面喷丸应变层与疲劳强度的关系

 喷丸强化工艺是用来提高金属零件疲劳和应力腐蚀断裂抗力的行之有效的工艺。因为它具有其它表面强化工艺无可比拟的优点,所以近年来在国内外,特别是航空工业中获得了迅速的发展。 有关喷丸强化对铝合金疲劳强度影响的研究指出,喷丸虽然能够改善疲劳S-N曲线高应力区的疲劳强度,但在疲劳强度极限附近,没有明显的效果。

RELATIONSHIP BETWEEN SHOT PEENING SURFACE STRAIN LAYER AND FATIGUE STRENGTH OF HIGH-STRENGTH ALUMINIUM ALLOYS

The relation of the fatigue behaviour to the residual stress and plastically deformed microstructure in the surface strain layer of high-strength aluminium alloys is investigated. It is shown that the stress and microstructure strengthenings are two factors improving the fatigue behaviour, moreover, the microstructure strengthening factor plays a main role in the improvement of the fatigue behaviour in the high alternating stress region of S-N curve, but the main contribution to the fatigue behaviour near the fatigue limit is made by the stress strengthening factor. There exists an optimum residual stress field induced by shot peening for a high-strength aluminium alloy, and the maximum compressive residual stress in the field is (σ_r)_op≈σ_s-σ_a.