Hits:

Date of Publication:2020-01-01

Journal:Material Science and Technology

Volume:28

Issue:6

Page Number:8-14

ISSN No.:1005-0299

Key Words:"electron beam melting; bulk tungsten; microstructure; density; microhardness"

CN No.:23-1345/TB

Abstract:Due to high melting point,the traditional preparation method of tungsten is powder metallurgy(PM).The prepared tungsten material has fine and uniform microstructure,but the density is not high enough.Low density of tungsten prepared by traditional powder metallurgy is a technical bottleneck that is difficult to break through,and thus deteriorates the performance of tungsten.There is an urgent need to develop new preparation techniques.In this study,98.3% of tungsten powder and 1.7% of carbon powder were uniformly mixed,then hot pressed at 1 800 ℃ and 26 MPa,and then smelted by electron beam melting technology.Its microstructure,density,and microhardness were evaluated by optical microscope,scanning electron microscope (SEM),and microhardness tester and compared with the performance of bulk tungsten prepared by traditional powder metallurgy.The results show that the tungsten ingot prepared by electron beam melting has excellent metallurgical quality,and the relative density can reach 99.8%.The microhardness value of the bulk tungsten reaches 9.16 GPa,which is significantly higher than that prepared by powder metallurgy,and breaks through the relationship between the density-microhardness of bulk tungsten prepared by traditional processes.After annealing heat treatment at 1 300 ℃ for 6 h,the microhardness decreased slightly and still had 8.86 GPa,showing the hardness performance advantages of electron beam melting in the preparation of bulk tungsten.

Note:新增回溯数据