ISSN:
1662-9752
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
This work analyses the changes induced on the microstructure and mechanical propertiesof ultrafine (0.2 and 0.4 μm) hardmetal grade WC-7wt.% Co by HIP after vacuum sintering. A largeHIP pressure (155 MPa) is applied to the ultrafine hardmetal system at different temperatures(1000, 1200 and 1400 °C). The well-known correlation between porosity reduction and fracturestrength improvement is confirmed. Residual porosity left after liquid phase sintering is removedmore effectively at HIP temperatures above the eutectic point of the alloy (1400 °C). In the absenceof grain growth inhibitors, hardness decreases continuously, and WC-Co ultrafine microstructurecoarsens as HIP temperature rises. However, for specimens containing VC and Cr3C2 additions,hardness increases as HIP temperature rises from 1200 to 1400 ºC. It is proposed that thisanomalous trend (confirmed by grain size observations) is related to the activation of coalescencemechanisms during solid state HIPing, which are inhibited by the presence of a liquid phase
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/17/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.560.121.pdf
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