hafnium carbide particles in the precipitation

Industrial production can be divided Molybdenum tube alloy Mo-Ti-Zr-based, Mo-W series and Mo-Re alloys, and hafnium carbide particles in the precipitation strengthening Mo-Hf-C based alloy. TZM alloy has excellent performance, is the most widely used molybdenum alloy. TZC (Mo-1.25 Ti-0.15 Zr-0.15C) TZM alloy has a higher temperature than the strength and the recrystallization temperature, but the processing difficulties, application is limited.
Molybdenum alloys and solder brittleness and low temperature brittleness temperature oxidation and other shortcomings, so the development is restricted. Alloying method using molybdenum alloy is difficult to improve the high temperature oxidation resistance, but at present, with a protective coating to improve this performance. Molybdenum alloys in the study of the problem is to improve the high temperature strength and the recrystallization temperature, to improve the low-temperature plastic material. Pure molybdenum material in the study of the problem is to improve the low-temperature ductility, i.e. reduce its plasticity - brittle transition temperature.
Molybdenum alloy is the main way to strengthen the solid solution strengthening, precipitation strengthening and hardening (see metal reinforced). Titanium, molybdenum, zirconium, and hafnium is the main alloying elements. Molybdenum alloying elements on the hardness of the rolling bar chart next page. Titanium, zirconium and hafnium can not only solid solution strengthening and maintaining the low-temperature plastic material, and can form a stable, dispersed carbide phase, to improve the strength and recrystallization temperature.
Interstitial impurities carbon, nitrogen, oxygen especially plastic - brittle transition temperature have serious implications. Their very low solubility in molybdenum (at room temperature of not more than 1ppm), excess interstitial elements molybdenum compound places distributed around the grain boundaries and reduce grain boundary strength, resulting in brittle intergranular fracture. Molybdenum alloy with traces of boron can refine the grain, clean grain boundaries and change the grain boundary morphology, thereby increasing the plasticity of molybdenum: adding trace elements such as iron and yttrium can also improve low-temperature plasticity (see screen). 1955 Mladic (G.Geach) and Hughes (J.Hughes) found that rhenium can significantly improve the ductility of molybdenum and tungsten, molybdenum make plastic - brittle transition temperature down to -200 ℃.