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在MTS-8032疲劳试验机上对不同时效状态的2A12铝合金进行轴向拉伸应力疲劳试验,并采用扫描电镜(SEM)分析该合金T6和T8时效状态对疲劳断口形貌的影响。结果表明:T6态(495℃×1 h水淬,190℃×8 h时效)和T8态(495℃×1 h水淬,预拉伸4%后进行190℃×6 h时效)2A12合金棒材,轴向疲劳寿命都随着应力水平的提高而降低。在较高应力水平如420 MPa,T6态和T8态合金的轴向疲劳寿命相近,都在105左右。而在较低应力水平如280 MPa,T8态合金的疲劳断裂循环周次较高。预变形处理提高合金300 MPa应力水平以下的疲劳寿命。T6态合金在107次的疲劳强度约为220 MPa,而T8态合金在107次的疲劳强度约为280 MPa。4%的预拉伸变形处理可以提高合金的疲劳强度。
The fatigue test of 2A12 aluminum alloy under different aging conditions was carried out on MTS-8032 fatigue tester, and the effect of aging conditions of T6 and T8 on the fatigue fracture morphology was analyzed by scanning electron microscope (SEM). The results show that the aging of 2A12 alloy rod in T6 state (495 ℃ × 1 h water quenching, 190 ℃ × 8 h aging) and T8 state (495 ℃ × 1 h water quenching, 4% pretensioning and 190 ℃ × 6 h aging) Material, axial fatigue life decreases with increasing stress levels. At higher stress levels, such as 420 MPa, T6 and T8 alloys have similar axial fatigue lives at about 105. At the lower stress level, such as 280 MPa, T8 alloy fatigue fracture cycle higher. Pre-deformation treatment increases the fatigue life of the alloy below 300 MPa stress level. The fatigue strength of T6 alloy is 107 MPa at 220 MPa, while that of T8 alloy is 107 MPa at 280 MPa. 4% pre-stretch deformation treatment can improve the fatigue strength of the alloy.