(華中科技大學 材料成形與模具國家重點實驗室，武漢 430074)
摘 要: 對壓鑄AlMgxSi2Mn(x=5.7~7.2)合金的微觀組織進行分析，測試力學性能以及疲勞性能，研究鎂含量對合金組織和力學性能的影響。結(jié)果表明：隨著Mg含量的提高，合金屈服強度和布氏硬度分別提高了10.4%和9%，伸長率從8.3%降低至4.5%，抗拉強度則沒有明顯變化。疲勞壽命隨著Mg含量的提高而提高，疲勞極限從57 MPa上升至75 MPa。合金的微觀組織主要由α(Al)和Mg2Si相組成，F(xiàn)e相則以顆粒狀的Al3Fe和不規(guī)則形狀的Al15(Fe,Mn)3Si2存在于晶界。Mn元素的加入也降低合金的粘模傾向。
關(guān)鍵字: 高壓壓鑄；鋁鎂合金；疲勞性能；微觀組織
（State Key Laboratory of Materials Processing and Die & Mould Technology,
Huazhong University of Science and Technology, Wuhan 430074, China）
Abstract:Microstructure observation, tensile test and fatigue tests were conducted to investigate the effect of magnesium content on microstructure and mechanical properties of die casting AlMgxSi2Mn (x=5.7-7.2) alloys. The results indicate that with magnesium content (mass fraction) increasing from 5.7% to 7.2%, the yield strength and brinell hardness increase by 10.4% and 9%, respectively. The elongation decreases from 8.3% to 4.5% and the ultimate tensile strength is stable. The fatigue life of alloys increases with enhanced magnesium contents and the fatigue limit increases from 57MPa to 75MPa. The microstructure of those alloys consists of α(Al) matrix and Mg2Si. Meanwhile, Al3Fe and Al15(Fe,Mn)3Si2 compounds distribute around grain boundaries. The addition of Mn reduces the die sticking tendency.
Key words: high pressures die casting; Al-Mg alloys; fatigue property; microstructure
