Abstract
Ti(C, N)-30mass%WC-5mass%Mo2C-20mass%Co was synthesized by a mechanical milling of Ti(C, N) powder, WC powder, Mo2C powder and Co powder for 1.8 ks in a dry process. The mechanical milling used a planetary ball milling. Various powders were prepared by changing a rotational speed of main disk, rotational speed of grinding bowl and the size of crushing ball. The obtained powders were sintered at 1693 K in a vacuum after the press forming. The effects of the absolute acceleration and the ball size in the mechanical milling on the mechanical properties of the sintered bodies were examined by the microstructural observation, the transverse rupture strength test and the Rockwell hardness A-scale test.
The homogenous powder mixture was accomplished by using the small size ball even in a dry milling. The large absolute acceleration promoted the formation of a brittle phase in the sintered body because of the adhesion improvement between hard particle and metal powder during the milling. In our experimental condition, it was suitable for the preparation of a homogeneous powder mixture to apply the absolute acceleration of 2.5-10 G using cemented carbide balls with 2 mm in diameter. Additionally, the compact prepared using the homogeneous mixture with high carbon content at 1653 K showed 1313 MPa in transverse rupture strength.
