稳恒强磁场对1420铝锂合金扩散连接性能及元素扩散的影响

采用金属镓作中间层,通过机械加压的方式制备了Al-Li/Al-Li和Al/Al-Li的扩散偶试样,在超导强磁场装置中对扩散偶试样进行真空热处理;通过剪切试验对经稳恒强磁场热处理后试样的连接强度进行了测试,通过EBSD和EDS对扩散偶界面处微观组织和界面附近Mg元素的含量与分布进行了观察与测量,并对1420铝锂合金中的Mg元素在1060纯铝中的扩散系数进行了计算. 结果表明,扩散连接接头抗剪强度随着磁感应强度的增加而增大,在热处理参数为:温度520 ℃、磁感应强度12 T、时间1 h时,接头抗剪强度达到最大188 MPa,为母材的94.2%,比无强磁场环境热处理的结合强度提高了168%;同时,随着磁感应强度的增加,1420铝锂合金中的Mg元素在1060纯铝中的扩散距离增加,扩散系数增大,12 T强磁场环境下比0 T(无磁场)环境下扩散系数提高了25%.

Effect of high uniform magnetic field on joining property and element diffusion of 1420 Al-Li Alloy

Diffusion couples of Al-Li/Al-Li and Al/ Al-Li were prepared by using gallium as interlayer under mechanical compression force. Later heat treatment in vacuum was carried out in a superconducting magnet and the joining property was studied by shearing test. Interfacial microstructure and element content distribution of Mg near the interface were studied by EBSD and EDS, and the diffusion coefficient of Mg element in 1420 Al-Li alloy to 1060 pure aluminum was calculated. The results show that a great improvement of the joining strength was found after the heat treatment under high uniform magnetic field. The shearing strength of the joint reaches to the highest of 188MPa, which is 94.2% of the base metal and 168% improved than the joints heat treated without high magnetic field at the heat treatment parameters of temperature 520℃, magnetic flux density 12T and time 1 h. What's more, the diffusion distance of Mg in 1420 Al-Li alloy to 1060 pure aluminum becomes longer and diffusion coefficient becomes larger with the increase of the magnetic flux density. The diffusion coefficient is improved by 25% under the magnetic flux density of 12T than environment without magnetic field.