Molybdenum zirconium hafnium carbon alloy (ZHM alloys) is kind of new type molybdenum alloy which is using molybdenum as matrix elements doping a certain amount of zirconium, hafnium, and carbon and production by powder metallurgy. The content of zirconium, hafnium, and carbon are as follow: zirconium content (mass fraction) is 0.4 to 0.7%; hafnium content is 1.2 to 2.1%; carbon content is 0.15 to 0.27%. Since molybdenum, zirconium, hafnium, carbon having excellent characteristics of high melting point and tensile strength, and therefore THM alloys have good high-temperature strength, low temperature ductility and workability. In addition, after the experiments found that the tensile strength of the ZHM alloy at room temperature is 40% to 50% higher than titanium zirconium molybdenum (TZM alloy). Currently, ZHM is the highest strength molybdenum alloy among other molybdenum alloys. Meanwhile, ZHM alloys compared to other molybdenum alloys have better creep resistance, higher recrystallization temperature and good weldability. Its main application is as a powder superalloy isothermal forging dies.
Molybdenum zirconium hafnium carbon alloy produced by powder metallurgy is mainly made of the production processes are as follows:
1. Mixing high-purity molybdenum powder with hydrogenated hafnium, zirconium hydride and carbon, then molds by cold isostatic pressing.
2. To sintering press-formed powder into ingots and then to forging at 1200 ℃. The amount of deformation is about 50% to 75% or higher and at the intermediate it will process hydrogen annealing for 8 hours at 1200 ℃.
ZHM alloys are still in the development stage, a different performance in the manufacturing process and heat treatment process will have a greater impact on alloy’s properties. Therefore to study better production processes of ZHM alloys is good for improving the performance of the alloy. So it can be widely applied to more areas. Many researchers predicted that ZHM alloys may become a super alloy is used in the future.
没有评论:
发表评论