Molybdenum-tungsten alloy
Molybdenum-based alloys containing 25% and 30% tungsten have excellent properties against molten zinc corrosion and can be used to fabricate molten zinc pumps and electrolytic zinc electrodes and to filter molten zinc.
Temperature characteristics properties (1) the melting point of molybdenum tungsten alloy increases with the increase of tungsten content. when the tungsten content increases to 25%, the melting point of the alloy is about 200°c higher than that of pure molybdenum. Therefore, the corresponding alloy composition can be selected in the range of 2620~3410°C according to the use temperature and the required alloy melting point. This advantage is also one of the advantages of molybdenum tungsten alloy being widely used.
Lattice constants The lattice constant and density of molybdenum tungsten alloy increase linearly with the increase of tungsten content. The hardness and strength of molybdenum tungsten alloy increase with the increase of tungsten content.
Hardness the highest room temperature hardness value of the alloy is between 90% and 100% of tungsten content, and its vickers hardness value is up to 3530–3860 mpa, which is more than twice higher than that of pure molybdenum. The highest high temperature hardness value of the alloy is between 70% and 85% of tungsten content. when the tungsten content increases from o to 40%, the room temperature tensile strength of the processed molybdenum tungsten alloy increases from 617 mpa to 900 mpa.
Hardness value of molybdenum tungsten alloy ingot smelted by vacuum arc The strengthening mechanism of binary molybdenum tungsten alloy is mainly solid solution strengthening and strain strengthening. When the alloy elements such as titanium, zirconium, niobium and carbon are added to the alloy, it causes obvious precipitation strengthening. The nominal compositions of commonly used molybdenum tungsten alloys are: Mo-20W, Mo-30W, Mo-50W, Mo-75W, Mo-90W, and Mo-25W-0.1Zr-0.03C, Mo-25W-1.67Nb-10.37Ti-0.12ZI-0.18C, etc.
