Microstructures of 'In Situ' Ti/TiB_w Composites Produced by a Liquid Manufacturing Route

摘要

The feasability of Ti/TiB_w composites synthetized by a liquid route has been investigated. The composites were prepared by melting a Ti-6Al-4V alloy mixed with TiB_2 or boron powders using an arc furnace in an argon atmosphere. The kinetics of dissolution of the boron and TiB_2 powders within the liquid titanium have been studied in order to determine the experimental conditions (temperature and melting duration). The microstructures of the reinforced Ti-6Al-4V alloys have been investigated and correlated to the casting conditions. It was found that the aspect ratio of TiB_w needles depends on the boron content. The precipitation of TiB_w has also a beneficial effect on the alpha grain size whereas the beta phase of the matrix is linked to the TiB_w .