Microstructure and mechanical properties of tungsten composites co-strengthened by dispersed TiC and La2O3 particles

Abstract

Abstract In order to improve the mechanical properties of tungsten, La 2 O 3 and TiC were added to tungsten. The La 2 O 3 –TiC/W composites were prepared by vacuum hot pressing, and the microstructure and mechanical properties of the composites were investigated. The results show that strengthening particles mostly existing at grain boundaries inhibit the growth of tungsten grains in sintering process. The La 2 O 3 –TiC/W composites have an average grain size of 0.5 μm, and the fine grains are helpful to improve the strength and toughness of composites. The addition of La 2 O 3 and TiC particles to tungsten matrix is beneficial to mechanical properties of tungsten. La 2 O 3 is beneficial to sintering and densification of composites to a certain extent. At the same time, TiC particles have good interface joint with adjacent tungsten matrices. This assures the load transferring to TiC particles when the composite suffers load. The co-strengthening effect of La 2 O 3 and TiC on tungsten is better than that of either La 2 O 3 or TiC. But the co-strengthening effect is deteriorated when the TiC content increases to a high level. The maximum of flexural strength and fracture toughness are 901 MPa and 10.07 MPa m 1/2 , respectively corresponding to the composition of 1 wt%La 2 O 3 –5 wt%TiC/W and 0.5 wt%La 2 O 3 –10 wt%TiC/W. According to the mechanical property tests, the composite has better general mechanical properties with addition of 1 wt%La 2 O 3 and 5 wt%TiC.