Polycrystalline cubic boron nitride sintered with Ti(C,N)-W-Al mechanically alloyed binders

The structural changes in Ti(C,N)-W-Al mechanically alloyed (MA) binders and the sintering mechanism of PcBN were investigated by XRD, SEM and TEM techniques. The elastic properties of PcBN compacted were determined by ultrasound technique. Tungsten was efficiently dissolved in Ti(C,N) by mechanical alloying, forming homogeneous binders during sintering. Opposite strain effects were induced in the binders than in PcBN particles. Dissolution of W in Ti(C,N) enhanced the fracturing of the cBN particles and the formation of the nanostructured binder pools by increasing the hardness of binder particles. Poisson's ratios and Young's moduli of the new PcBN products were higher than the reference product. Micro-Vickers hardness of sintered products increased with milling time of the binder powder. Slightly higher hardness values were achieved when Al powder was mechanically alloyed with Ti(C,N) and W powders than when it was attrition milled with MA Ti(C,N)-W.