Aluminum Alloy, Titanium Alloy Electron Beam Welded Joints, Performance And Welding Performance Study

The lightweight alloy material applied commonly in national defense, astronautics, aviation industry because it has the characteristics such as high specific tenacity, corrosion resistance, the heat-resisting performance. But its weldability is bad and its processing craft is not good. The high-energy density welding about lightweight alloy is the hotspot of world welding craft research. Therefore, the research on microstructure; mechanical properties and welding properties of electron beam welding joints of the aluminium alloy and titanium alloy not only may enrich the electron-beam welding theory knowledge, but also has important significant meaning to production guiding.In this paper, the microstructure; mechanical properties and fracture appearance characteristic of electron beam welding joints of 6061-T6 aluminum alloy which applied commonly in national defence industry were studied by means of metallography,mechanical test and SEM technology. In addition, Based on Electron beam welding tests of aluminium alloy,this paper emphases on pore tendence of welding zone by altering method of clearing of slope surface before welding; removing gas of welding piece; altering technical parameter; preheating; remelting and reason why there exist crack in welding zone. At the same time, the microstructure; mechanical properties and fracture appearance characteristic of electron beam welding joints of TC4 titanium alloy which applied commonly in aviation industries were studied by means of metallography,mechanical test and SEM technology. The important outcomes are introduced as following:â’ˆIf the welding sample of aluminium alloy under feasible technical parameter are grinded with the thin sandpaper at first, and then cleaned with acetone before welding, the pore number in weld zone is least. The heat-input is higher, the pore number is less. Preheating and remelting not only can modify surface of welding seam of aluminium alloy, but also can decrease pore number in welding seam.â’‰The tensile strength; plasticity and hardness in weld zone and heat-affected zone of welding samples of aluminium alloy welded by EBW are by far higher than that welded by TIG although they decrease because equiaxed grains and fir-tree crystal become gross and the number of Mg2Si phase decrease evidently by preheating and remelting.â’ŠAlong with the thickness of welding slice increases, the crack rate reduces...