The development of advanced materials using novel powder metallurgy processes

直接粉末轧制(DPR)是一种首先将金属粉末压制成多孔板或带材的工艺。然后，在一种称为烧结的过程中对这种带材进行加热，使单个颗粒粘合并融合在一起。最后一步是冷轧这种多孔的烧结带，以减少其厚度并增加其密度，理想的做法是消除所有气孔。在钛及其合金的情况下，低成本粉末原料的可用性与DPR工艺相结合，是为一系列工业应用生产低成本钛板或钛箔的潜在方法。然而，到目前为止，应用于钛粉的DPR工艺还没有生产出具有广泛商业应用所需的力学性能的薄板。这限制了钛在许多应用中的使用。在这项计划中，我们将利用独特的辊压和冷轧设备来研究和优化从低成本粉末生产钛板的DPR方法。冷轧机组具有独特的测量冷轧减薄过程中轧制力的能力。这将使对多孔性金属的轧制力学和致密化的定量研究得以完成。磨机中的单个轧辊可以以不同的速度旋转，从而可以执行不对称轧制。预计不对称轧制将加速多孔板的致密化，并创造出精细的微观结构。这两个特征共同作用，应该可以生产出机械性能更好的板材。通过这项研究取得的基本认识将有助于发展深冲成形工艺、板材组织和力学性能之间的关系。反过来，这项工作有可能突破目前从低成本粉末中提取的钛片材料的性能障碍。这将增加这种轻金属在加拿大航空航天和汽车行业的使用，有助于减轻重量，降低燃油经济性，最终减少温室气体排放。

Direct powder rolling (DPR) is a process where metallic powders are first compacted into a porous sheet or strip. This strip is then heated in a process known as sintering to allow the individual particles to bond and fuse together. The final step is to cold roll this porous, sintered strip to reduce its thickness and increase its density, ideally removing all the pores. In the case of Titanium and its alloys, the availability of a low-cost powder feedstock, in conjunction with the DPR process, is a potential way to produce lower cost Titanium sheet or foil for a range of industrial applications. However, to date the DPR process applied to Ti powder has not produced sheet with mechanical properties necessary for widespread commercial use. This has limited the use of Titanium in many applications. In this proposal, we will take advantage of unique roll compaction and cold rolling equipment to investigate and optimize the DPR method for producing Ti sheet from low cost powders. The cold rolling mill has the unique capability of measuring the roll force during cold rolling and thickness reduction. This will allow a quantitive study of roll mechanics and densification of porous metals to be completed. The individual rolls in the mill can be rotated at different speeds which allows asymmetric rolling to be performed. It is anticipated that asymmetric rolling will accelerate densification of the porous sheet and create a refined microstructure. Both these features acting together should produce sheets with improved mechanical properties. The fundamental understanding achieved through this research will lead to the development of the relationship between the DPR process, sheet microstructure and mechanical properties. In turn, the work has the potential to break through the current performance barrier of Ti sheet materials derived from low cost powders. This will increase the use of this light metal in the Canadian aerospace and automotive industries, facilitating weight reduction, lower fuel economy and ultimately a reduction in greenhouse gases.