High-density tungsten alloy has a series of excellent properties such as high density, high strength, good ductility, good machining performance, low linear expansion coefficient, high thermal conductivity, good oxidation and corrosion resistance, good weldability and so on. These excellent properties make it widely used in high-tech fields, military and civil industries, such as balance weight components, conventional components, ray shielding materials, etc. Among them, high-density tungsten alloy has good rigidity and easy shape maintenance, which is an ideal nuclear fuel storage and radiation shielding material. At the same time, W-Ni-Fe alloy has a series of excellent properties, such as high melting point, good impact toughness, high plasticity and low yield strength, can be used to manufacture a thin-walled large chain shell, as a functional composite material used in atomic energy explosion, to ensure the normal operation of the instrument.
Tantalum alloy with high density, high melting point, good corrosion resistance, excellent high temperature strength, workability, weldability and low plastic/brittle transition temperature, excellent dynamic mechanical properties and surface density, stable, high dielectric constant of the amorphous oxide film and other characteristics, widely used in electronic, chemical, aerospace, weapons, and other fields. So in order to more fully play their respective advantages of the high density tungsten alloy and tantalum alloy, in the high-tech fields such as aerospace, dynamic high-pressure physics, nuclear fusion, has important applications in areas such as weapons, and to adopt effective welding technology, to obtain high quality high density tungsten alloy and tantalum alloy welded joint of dissimilar metal materials.
Defects in direct welding joints of tungsten alloy and tantalum alloy lead to low corrosion resistance and reduced service life of materials. The welding strength was improved after the welding temperature was further improved, but the fracture toughness of the material was reduced due to the recrystallization and grain coarsening of W and Ta. The decrease of welding temperature will lead to the decrease of welding strength; At the same time, Ta begins to oxidize when heated to 200°C, and rapidly oxidizes above 500°C, and has the characteristics of absorbing hydrogen, oxygen and nitrogen. A small amount of gaseous impurities will have a strong impact on its organizational structure and mechanical properties.
