The sintering of high-density tungsten alloys mostly uses a liquid phase sintering process: in general, the sintering temperature is higher than the liquid phase temperature by 20~60℃. The sintering temperature of W-Ni-Fe is 1500~1525℃, and the sintering density can be close to the theoretical density. The holding time is generally 60~90minutes, if it exceeds 120 minutes, the performance will decrease.
The use of higher sintering temperature and shorter holding time is beneficial to improve the tensile strength and elongation of the alloy. The choice of cooling rate is related to the ratio of Ni and Fe of the alloy. When this ratio is not in the range of generating brittle compounds, such as the ratio of Ni and Fe is 2 ~ 4, any cooling rate will not generate intermetallic compounds. To avoid brittleness and reduce porosity, it is beneficial to use an appropriate cooling rate.
