(大連理工大學(xué) 材料科學(xué)與工程學(xué)院，大連 116024)
摘 要: 采用鑄錠冶金工藝制備6種Gd含量不同的A1-Zn-Mg-Cu-Zr-xGd合金。采用金相觀察、力學(xué)性能測試、掃描電鏡、電子探針及透射電鏡等分析手段，研究質(zhì)量分數(shù)x，分別為0%、0.10%、0.15%、0.20%、0.25%和0.30%的Gd對基體合金鑄態(tài)及時效態(tài)顯微組織和力學(xué)性能的影響。結(jié)果表明：Gd含量對A1-Zn-Mg-Cu-Zr合金的微觀組織和力學(xué)性能的影響顯著，當Gd含量低于0.25%時，隨Gd含量的增加細化效果、強度以及伸長率都增加；當Gd含量為0.25%時，鑄態(tài)組織中基體晶粒最小，達到32 μm左右；此時T6態(tài)合金組織的強度和伸長率達到最高，抗拉強為624.54 MPa，屈服強度為595.00 MPa，伸長率為13.3%，且固溶組織具有良好的抗再結(jié)晶作用；而當Gd含量超過0.25%時，合金的微觀的組織與力學(xué)性能變差。
關(guān)鍵字: A1-Zn-Mg-Cu-Zr合金；Gd；顯微組織；力學(xué)性能
（School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, China）
Abstract:Six kinds of Al-Zn-Mg-Cu-Zr-xGd alloys with different Gd contents were prepared by cast metallurgical process. The compositional dependence of the casting structure, tensile properties was investigated for Al-Zn-Mg-Cu-Zr-xGd alloys(x=0%, 0.10%, 0.15%, 0.20%, 0.25%, and 0.30%, mass fraction) by optical microscopy (OM), tensile test, scanning electron microscopy (SEM), electronic probe microanalysis (EPMA) and transmission electronic microscopy (TEM). The results show that, with the increase of Gd content, the structure and the mechanical properties of A1-Zn-Mg-Cu-Zr-Gd alloy are improved. When the alloy contains 0.25% Gd, the alloy gets the finest microstructure, with grain size of about 32 μm. And the maximum ultimate tensile strength and yield strength are obtained in peak-aged state, and the values are 624.54 MPa and 595.00 MPa, respectively at T6 while the elongation is 13.3%. The role of anti-recrystallization is obvious in the solution structure. However, when the content of Gd exceeds 0.25%, the microstructure and properties of alloy appear certain deterioration.
Key words: A1-Zn-Mg-Cu-Zr alloy; Gd; microstructure; mechanical properties
