si3n42024al铝基复合材料钎焊连接工艺及性能分析-brazing process and performance analysis of si 3n 42024 al - based composite.docx

摘 要Si 两种元素与 Ti 活性层反应生成的针状 Ti- Al-Si 三元化合物贯穿该反应层，Ti层提高了钎料对于母材的润湿性，接头剪切强度比未溅射沉积 Ti 层提高了 8 倍， 最大可达 83.96MPa。关键词：Si3N4/2024Al 铝基复合材料；钎焊；微观组织；界面反应；力学性能AbstractHigh- volume content of ceramic reinforced a luminum matrix composites have characteristics of light weight, high strength, high stiffness ratio, adjustable coefficient of thermal expansion, etc. In the light electronic packaging, thermal control components and other areas have extensive application prospects. However, due to the constraints of connectivity, high- volume content of ceramic reinforced aluminum matrix composite materials will be restricted.In this paper, three different brazes were usesd to join Si3N4/2024Al aluminum matrix composite between itself. Untreated Si3N4/2024Al aluminum matrix composite was welded by Sn- Zn- Ti alloy. Also, the Si3N4/2024Al aluminum matrixcomposite which was sputtered Al coating on the surface, was welded by Zn- Al、Al-Si-Mg alloy. While the will Si3N4/2024Al aluminum matrix composite, which was chemical nickel-plating on the surface, was welded by Sn- Ag-Cu filler. The mechanis m of joining Si3N4/2024Al was studied.In this paper, we find that a obvious diffusion layer was generated between theelement Sn diffused to the Si3N4/2024Al aluminum matrix composite and the Si3N4/2024Al aluminum matrix composite. The mechanism of Sn diffus ion was analyzed by Young’s equation and Cavity theory and we got that the vaporation of Zn in vacuum and the exist of second phase strengthening particles were necessary to accomplish Sn diffuisive layer. Sn- Zn alloy is employed to conduct wetting tests over Si3N4/2024Al composite (45% Si3N4) in vacuum under different temperatures and different welding t ime. O n surface of the composite formed a thick Sn diffus ion layer, and the the layer grows thicker as temperature increases. while diffusion is notobserved when temperature is below 330℃. The microstructure and mechanical properties of the joint between aluminum matrix composites with a