Molybdenum and its alloy plates
Molybdenum and molybdenum alloy have high melting point, high temperature strength, low creep rate at high temperature, good thermal shock resistance, and have good thermal conductivity, low linear expansion coefficient and sputtering rate, etc., are widely used in aerospace, weapons electronics, nuclear power medical, LED and other fields. With the development of science and technology, more and more occasions need to use large specifications of high-performance molybdenum alloy sheet, subject to the influence of equipment, technology accumulation and other aspects, the commonly used solution is generally spliced, but the spliced sheet has high temperature variability, insufficient strength, poor accuracy and other shortcomings.
For molybdenum alloy plate with a single weight of more than 500kg, the preparation process has the following difficulties: 1) Due to the poor fluidity of molybdenum alloy powder, the conventional powder loading process is easy to cause problems such as compact head size and plate surface warping, and the traditional demoulding process is used for large single weight slab, which is difficult to demoulding, such as improper operation, it is easy to cause compact fracture; 2) The multi-phase large-size ingot is cracked and the microstructure properties are not equal due to the different expansion of each phase during the sintering process; 3) The uneven distribution of residual stress in the rolling deformation process of large-size ingot leads to slab cracking and uneven microstructure and properties.
By introducing titanium, zirconium, hafnium, carbon and other elements into molybdenum matrix, titanium and zirconium can form solid solution with molybdenum and play the role of solid solution strengthening. The formation of carbon and titanium, zirconium, hafnium and other dispersed carbide phase to hinder the growth of molybdenum grains can not only play the role of fine crystal strengthening, but also achieve the effect of dispersion strengthening, which can further improve the mechanical properties and recrystallization temperature of the material, and expand the application range of the material.
