稳定化处理对Al-Si合金疲劳性能的影响
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摘要
研究了稳定化处理对Al-Si合金疲劳性能与组织的影响。对稳定化处理后Al-Si合金进行高温(350℃)旋弯疲劳试验,观察合金材料的疲劳断口、显微组织与析出相。结果表明:稳定化处理后,Al-Si合金高温疲劳寿命比T6态处理的合金提高了4倍以上;合金组织中,初晶Si圆整化程度提高,长条状的共晶Si颗粒化,均匀弥散分布在基体中,合金塑性提高了1倍以上;稳定化处理后,基体中弥散析出大量细小的Al_2Cu相,阻碍位错运动,从而提高了Al-Si合金疲劳寿命。
The effects of stabilization treatment on the fatigue properties and microstructure of Al-Si alloy were studied.The high temperature(350 ℃) bending fatigue test of Al-Si alloy after stabilization was carried out. The fatigue fracture,microstructure and precipitated phase of the alloy were observed. The results show that, the high temperature fatigue life of Al-Si alloy is more than 4 times longer than that of T6 alloy after stabilization treatment. In the microstructure of alloy, the degree of primary Si roundening is improved, and the strip eutectic Si becomes globular and is uniformly distributed in the matrix, the plasticity of the alloy increases 1 time above. After stabilization, a large number of fine Al_2Cu phases are precipitated dispersvely in the matrix, and they hinder dislocation movement. Thus, the fatigue life of Al-Si alloy is improved.
The effects of stabilization treatment on the fatigue properties and microstructure of Al-Si alloy were studied.The high temperature(350 ℃) bending fatigue test of Al-Si alloy after stabilization was carried out. The fatigue fracture,microstructure and precipitated phase of the alloy were observed. The results show that, the high temperature fatigue life of Al-Si alloy is more than 4 times longer than that of T6 alloy after stabilization treatment. In the microstructure of alloy, the degree of primary Si roundening is improved, and the strip eutectic Si becomes globular and is uniformly distributed in the matrix, the plasticity of the alloy increases 1 time above. After stabilization, a large number of fine Al_2Cu phases are precipitated dispersvely in the matrix, and they hinder dislocation movement. Thus, the fatigue life of Al-Si alloy is improved.
引文
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[8]Lados D A,Apelian D,Major J F.Fatigue crack growth mechanisms at the microstructure scale in Al-Si-Mg cast alloys:Mechanisms in regionsⅡand III[J].Acta Materialia,2006,54(6):1475-1486.
[9]曹思婷,郭永春,夏峰.微观组织对Al-Si活塞合金高周疲劳性能的影响[J].热加工工艺,2018,47(6):83-87.
[2]郭金宝.高功率柴油机活塞可靠性分析及试验研究[D].济南:山东大学,2007.
[3]Joyce M R,Styles C M,Reed P A S.Elevated temperature short crack fatigue behaviour in near eutectic Al-Si alloys[J].Int J Fatigue,2003,25(9-11):863-869.
[4]Nicoletto G,Riva E,Di Filippo A.High temperature fatigue behavior of eutectic Al-Si-alloys used for piston production[J].Procedia Engineering,2014,74:157-160.
[5]Gall K,Horstemeyer M,Mcdowell D L,et al.Finite element analysis of the stress distributions near damaged Si particle clusters in cast Al-Si alloys[J].Mechanics of Materials,2000,32(5):277-301.
[6]Gall K,Horstemeyer M F,Degner B W,et al.On the driving force for fatigue crack formation from inclusions and voids in a cast A356 aluminum alloy[J].International Journal of Fracture,2001,108(3):207-233.
[7]Lados D A,Apelian D.Relationships between microstructure and fatigue crack propagation paths in Al-Si-Mg cast alloys[J].Engineering Fracture Mechanics,2008,75(3):821-832.
[8]Lados D A,Apelian D,Major J F.Fatigue crack growth mechanisms at the microstructure scale in Al-Si-Mg cast alloys:Mechanisms in regionsⅡand III[J].Acta Materialia,2006,54(6):1475-1486.
[9]曹思婷,郭永春,夏峰.微观组织对Al-Si活塞合金高周疲劳性能的影响[J].热加工工艺,2018,47(6):83-87.