組織與性能的影響
(1. 中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083；2. 東北輕合金有限責(zé)任公司，哈爾濱 150060)
摘 要: 采用硬度測試、室溫拉伸性能測試、金相顯微和透射電鏡研究微量鈧對Al-Zn-Mg-Zr熱軋板攪拌摩擦焊接頭組織與性能的影響。結(jié)果表明：微量鈧使Al-Zn-Mg-Zr合金母材的抗拉強(qiáng)度和屈服強(qiáng)度分別提高22 MPa和42 MPa，使焊接接頭的抗拉強(qiáng)度和屈服強(qiáng)度分別提高19 MPa和33 MPa；焊核處硬度的提高來源于攪拌摩擦引起的細(xì)晶強(qiáng)化、固溶強(qiáng)化以及第二相的彌散強(qiáng)化，熱影響區(qū)硬度的降低則是由于焊接熱循環(huán)引起的析出相的粗化；微量鈧使Al-Zn-Mg-Zr合金母材及焊接接頭強(qiáng)度的提高的主要原因是細(xì)晶強(qiáng)化和Al3(Sc,Zr)粒子的析出強(qiáng)化。
關(guān)鍵字: 微量鈧；攪拌摩擦焊；顯微組織；性能
of Al-Zn-Mg-Zr hot rolled plate
（1. School of Materials Science and Engineering, Central South University, Changsha 410083, China;
2. Northeast Light Alloy Co., Ltd., Harbin 150060, China）
Abstract:The effects of minor Sc on the microstructures and mechanical properties of friction stir welding (FSW) joint of Al-Zn-Mg-Zr alloy were studied by hardness test, tensile property test, optical microscope (OM) and transmission electron microscope (TEM) analysis. The results show that minor Sc can increase the tensile strength and yield strength of Al-Zn-Mg-Zr based alloys by 22 MPa and 42 MPa and those of FSW joints by 19 MPa and 33 MPa, respectively. The strengthening of weld nugget attributes to grain refinement strengthening, solution strengthening and precipitation strengthening caused by friction stir welding. The decrease of strength in head affected zone (HAZ) is due to coarsening of precipitated phase. The fine grain strengthening and precipitation strengthening of Al3(Sc,Zr) should be responsible for the strengthening of base alloy and the joint of Al-Zn-Mg-Zr alloy with minor Sc.
Key words: minor Sc; friction stir welding; microstructure; mechanical properties
