(華南理工大學 機械與汽車工程學院，廣州 510640)
摘 要: 采用拉伸性能測試、定量金相分析、掃描電鏡等手段研究擠壓鑄造Al-5.0Cu-0.6Mn-0.5Fe合金的顯微組織和力學性能，分析擠壓壓力對合金的力學性能和顯微組織的影響。結果表明：當擠壓壓力從0增大到75 MPa時，合金的抗拉強度(σb)和伸長率(δ)都顯著增加。當擠壓壓力為75 MPa時，鑄態(tài)合金的抗拉強度為298 MPa，伸長率達17.6%；經T5熱處理后，合金的抗拉強度為395 MPa，伸長率為14.2%。當擠壓壓力從0增大到75 MPa時，α(Al)二次枝晶間距減小了69%，θ相(Al2Cu)和富Fe相的體積分數(shù)略有降低，針狀β-Fe相消失，同時晶界處漢字狀α-Fe相由連續(xù)的漢字狀變成分散、細小的骨骼狀。
關鍵字: 鋁合金；擠壓鑄造；顯微組織； 力學性能
（School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640, China）
Abstract:The microstructure and mechanical properties of Al-5.0Cu-0.6Mn-0.5Fe alloy prepared by squeeze casting were studied by tensile test, image analysis and scanning electron microscope. The effects of applied pressure on the microstructure and mechanical properties of the alloy were investigated. The results show that the ultimate tensile strength (σb) and elongation (δ) of the alloy increase significantly with increasing the applied pressure from 0 to 75 MPa. When the applied pressure is 75 MPa, the σb and δ of the alloy are 298 MPa and 17.6% in as-cast condition and 395 MPa and 14.2% after T5 heat treatment, respectively. When the applied pressure increases from 0 to 75 MPa, the second dendritic arm spacing of α(Al) decreases by 69%, the volume fractions of θ(Al2Cu) phase and the iron-rich intermetallic phases decrease slightly, the platelet β-Fe phases disappear, and the continuous Chinese script α-Fe phases at the grain boundary become more dispersive and smaller.
Key words: aluminum alloy; squeeze casting; microstructure; mechanical property
