(華南理工大學(xué) 廣東省金屬新材料制備與成形重點(diǎn)實(shí)驗(yàn)室，廣州 510640)
摘 要: 利用ProCAST軟件對(duì)不同壁厚(5~30 mm)階梯件的充型和凝固過程進(jìn)行模擬，結(jié)合模擬結(jié)果進(jìn)行澆注實(shí)驗(yàn)，重點(diǎn)研究壁厚對(duì)3D打印砂型鑄造Al-7Si-0.4Mg合金的微觀組織和力學(xué)性能的影響。結(jié)果表明：隨著壁厚減小，合金中α(Al)的二次枝晶臂間距、共晶硅尺寸以及含F(xiàn)e相的尺寸均減小；而合金的致密度和拉伸力學(xué)性能顯著升高。T6態(tài)下，合金的最高(壁厚5 mm)抗拉強(qiáng)度為279 MPa，斷后伸長(zhǎng)率為2.13%。隨著壁厚減小，合金的凝固冷卻速度增加，組織得到細(xì)化，致密度提高，合金的強(qiáng)度和伸長(zhǎng)率提高。此外，3D打印砂型鑄造的鋁合金性能受到砂模粘結(jié)劑含量的制約，斷后伸長(zhǎng)率較低。
關(guān)鍵字: 砂型3D打印；鑄造鋁合金；ProCAST模擬；組織；力學(xué)性能
（Guangdong Provincial Key Laboratory for Processing and Forming of Advanced Merallic Materials, South China University of Technology, Guangzhou 510640, China）
Abstract:ProCAST software was used to simulate the filling and solidification process of step parts with different thicknesses (5-30 mm), and the casting experiment was carried out in combination with the simulation results, the effects of thickness on the microstructure and mechanical properties of 3D printing sand casting Al-7Si-0.4Mg alloy were studied. The results show that, as the wall thickness decreases, the secondary dendrite arm spacing, eutectic silicon size, and Fe-containing phase size of α(Al) in the alloy decrease, while the density and tensile mechanical properties of the alloy increase significantly. In the T6 state, the highest (thickness of 5 mm) tensile strength of the alloy is 279 MPa, and the elongation after break is 2.13%. According to the analysis, as the thickness decreases, the solidification cooling rate of the alloy increases, the microstructure is refined, the density is increased, and the strength and elongation of the alloy are improved. In addition, the properties of 3D printings and casting aluminum are limited by the sand mold binder content, and the elongation is low.
Key words: 3D sand printing; cast aluminum alloy; ProCAST simulation; microstructure; mechanical properties
