Manufacturing process and mechanical properties of BJ3DP tungsten heavy alloy components

Binder jetting 3D printing (BJ3DP) is an emerging technology that can enable the production of tungsten heavy alloy (WHA) parts of great geometric complexity. Despite its promise, the industrial use of BJ3DP is today hindered by two shortcomings: (i) Printed parts have low strength in the as-cured state, and (ii) the mechanical properties of the sintered parts are poor when sintered using standard sintering practice. This study was carried out to address those shortcomings. We introduce a new WHA powder for BJ3DP and compare it to existing powders [ 1]. Physical properties (flow, apparent density, size distribution) and the green strength after BJ3DP are reported. Sintering and microstructural evolution differences between the new WHA powder, existing WHA powders for BJ3DP and conventional press-and-sinter WHA powders were investigated. Good densification during the early stages of sintering enabled the sintering of the new powder to full density. After sintering, mechanical properties of the printed specimens were evaluated and compared to the properties of cold isostatically pressed WHA specimens using conventional powder blends with similar chemistry. The new powder has superior green strength in the as-printed condition and is therefore a better candidate for the manufacturing of complex parts. It also sinters much faster than currently available powders and achieves mechanical properties that match those of conventionally processed WHA.