中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
Vol. 15 No. 2 April 2005 |
(School of Materials Science and Engineering, Harbin Institute of Technology,
Harbin 150001, China)
Abstract:Small amounts of nanocrystalline Al2O3 particles were doped in WC-Co nanocrystalline powders to study their reinforcing effects, and spark plasma sintering technique was used to fabricate the WC-Co- Al2O3 nanocomposites. Experimental results show that the use of Al2O3 nanoparticles as dispersions to reinforce WC-Co composites can increase the hardness, especially the transverse rupture strength of the WC-Co hardmetal. With addition of 0.5%(mass fraction) Al2O3 nanoparticles, the spark plasma sintered WC-7Co-0.5 Al2O3 nanocomposites exhibit hardness of 21.22GPa and transverse rupture strength of 3548MPa. The fracture surface of the WC-7Co-0.5 Al2O3 nanocomposites mainly fracture with transcrystalline rupture mode. The reinforcing mechanism is maybe related to the hindrance effect of microcracks propagation and the pinning effect for the dislocations movement, as well as the residual compressive strength due to the Al2O3 nanoparticles doped.
Key words: nanocomposites; WC-Co- Al2O3; mechanical properties; spark plasma sintering