铝合金散热器真空钎焊及热处理工艺研究

Study on Vacuum Brazing and Heat Treatment Process of An Aluminum Alloy Radiator

对Al-Mg-Si系铝合金散热器进行了真空钎焊及固溶时效处理的工艺研究,首先进行热分析得出母材的固相线及钎料的液相线温度,确定了真空钎焊参数,再采用X射线衍射仪对钎料、母材及该真空钎焊焊缝进行物相测试,最后通过微观组织观察及力学性能对比对不同工艺热处理的焊缝进行了深入分析。结果表明:608℃/70 min的真空钎焊工艺可获得优质的焊缝,未出现裂纹、孔洞及溶蚀等缺陷。随固溶温度提高,焊缝晶粒尺寸及初生相溶解度增大,焊缝最佳热处理工艺为530℃/3 h+150℃/5 h;在550℃/5 h时母材的初生相固溶度达到饱和,在150℃保温9 h时效处理时,可观察到大量的针状β"相和杆状β’相,母材最佳热处理工艺为550℃/5 h+150℃/9 h;经优化对比,散热器的热处理工艺为540℃/4 h+150℃/6 h,在该工艺下焊缝与母材的力学性能得到有效保证。

The vacuum brazing and solution+aging treatment of the Al-Mg-Si aluminum alloy radiators were studied.Firstly,the solidus temperature of the base material and the liquidus temperature of the brazer were determined by thermal analysis,then the vacuum brazing parameters were determined.Secondly,the phases of the brazer,base metal and the vacuum brazing weld were tested by X-ray diffractometer.Finally,the microstructure and the mechanical properties of the weld treated by different process were analyzed.The results show that high quality weld can be acquired under vacuum brazing process of 608 ℃/70 min,and there are no defects such as crack,hole,dissolution.With the increase of solution temperature,the grain size and primary phase's solubility of the weld increase.The appropriate heat treatment process of the weld is 530 ℃/3 h and150 ℃/5 h.Under solution treatment of 550 ℃/5 h,the primary phase's solubility of the base metal is maximum,and under the aging treatment of 150 ℃ for 9 h,a mass of needle-shape β" and rod-shape β' phase appear.The optimal heat treatment process of the base metal is 550 ℃/5 h+150 ℃/9 h.By optimization and comparison,the heat treatment process of the radiator is 540 ℃/4 h and 150 ℃/6 h,under the process the mechanical properties of the weld and the base metal can be guaranteed.