Fabrication of nano-crystalline W-Ni-Fe alloy with Mo and rare earth element additives
(1. School of Physics Science and Technology, Central South University,
Changsha 410083, China;
2. Department of Materials Science and Engineering,
Nanchang Institute of Aeronautical Technology, Nanchang 330034, China)
Changsha 410083, China;
2. Department of Materials Science and Engineering,
Nanchang Institute of Aeronautical Technology, Nanchang 330034, China)
Abstract: Three kinds of nano-crystalline high density alloys(86W-7Ni-3Fe-4Mo, 90W-4Ni-2Fe-4Mo and 90W-4Ni-2Fe-3.8Mo-0.2RE) were fabricated by a technique combining lower temperature vacuum sintering with high-energy ball milling mechanical alloying. The crystalline size and microstructures of the specimens sintered at different sintering temperatures were examined by X-ray diffraction(XRD) and scanning electron microscope(SEM). The results show that the optimal sintering temperature of 86W-7Ni-3Fe-4Mo, 90W-4Ni-2Fe-4Mo and 90W-4Ni-2Fe-3.8Mo-0.2RE alloys are 1300-1350℃. When they are sintered at 1300℃ for 75min, the hardness of three kinds of specimens can reach above HRC30, the relative density can reach above 96%, and 90W-4Ni-2Fe-3.8Mo-0.2RE alloy possesses the best integrated properties, its hardness is HRC35 and its relative density is 98%.
Key words: tungsten high density alloys; nano-crystalline; mechanical alloying; lower temperature sintering