预变形对超高强Al-Zn-Mg-Cu合金时效组织与力学性能的影响  

Effect of Pre-Deformation on Microstructure and Mechanical Properties of Ultra-High Strength Al-Zn-Mg-Cu Alloy After Ageing Treatment

作　　者：韩宝帅 魏立军 徐严谨 马晓光 刘雅菲 侯红亮 HAN Baoshuai;WEI Lijun;XU Yanjin;MA Xiaoguang;LIU Yafei;HOU Hongliang(AVIC Manufacturing Technology Institute,Beijing 100024,China;School of Materials Science and Engineering,Beihang University,Beijing 100083,China)

机构地区：[1]中国航空制造技术研究院,北京100024 [2]北京航空航天大学材料科学与工程学院,北京100083

出　　处：《金属学报》2020年第7期1007-1014,共8页Acta Metallurgica Sinica

基　　金：国防基础科研项目No.JCKY2017205B032;国家自然科学基金项目No.51971206。

摘　　要：利用TEM、XRD、SEM、DSC以及室温拉伸等方法,研究了预变形对超高强Al-Zn-Mg-Cu合金组织与性能的影响。通过对比未经预变形和预变形量为3%及4%的Al-Zn-Mg-Cu合金时效态微观组织与拉伸力学性能,发现:预变形可以提高铝合金时效析出速率和密度,变形量为3%时可促进析出相在晶内弥散分布,但增加到4%会导致析出相粗化;经预变形处理后晶间析出相尺寸减小,晶界无析出带宽度降低;抗拉强度和屈服强度提高,伸长率略微提高,经3%预变形以及80℃、12 h和120℃、8 h时效后的抗拉强度可达到(813±4) MPa,伸长率为10.10%±0.77%。分析认为,预变形产生的位错为析出相形核提供了异质形核的质点,改善了其在晶内与晶间的分布状态。Ultra-high strength Al-Zn-Mg-Cu alloy is a promising lightweight structural material,and there is still room to improve its mechanical property.As a typical precipitation strengthening material,controlling the size and distribution of precipitate is an effective way to enhance the mechanical properties of the ultra-high strength Al-Zn-Mg-Cu alloy.The influence of pre-deformation on the microstructures and properties of the ultra-high strength Al-Zn-Mg-Cu alloy after ageing treatment was studied by TEM,XRD,SEM,DSC and tensile tests.The microstructures and the tensile mechanical properties of Al-Zn-Mg-Cu alloy without pre-deformation and with 3%and 4%pre-deformation were compared.It is found that the pre-deformation can promote the ageing precipitation rate and enhance the precipitate density in the Al-Zn-Mg-Cu alloy,and the pre-deformation ratio of 3%can promote the dispersion of the precipitate phase in the grain interiors,but the pre-deformation ratio of 4%may result in coarsening of precipitate.The size of precipitate along the grain boundaries and the width of precipitation free zones decreased in the pre-deformation treated ultra-high strength Al-Zn-Mg-Cu alloys.The tensile strength and yield strength of the pre-deformation treated ultra-high strength Al-Zn-Mg-Cu alloys increased,and the elongation also increased slightly,in which the tensile strength and elongation of 3%pre-deformation alloy combined with 80℃for 12 h and 120℃for 8 h ageing were(813±4)MPa and 10.10%±0.77%,respectively.The results show that the dislocations produced by pre-deformation may provide more heterogeneous nucleation sites for the precipitate formation,and improve the precipitate's distribution.

关 键 词：超高强铝合金 预变形 析出相 晶间无析出带 力学性能 

分 类 号：TG379[金属学及工艺—金属压力加工]