On Powder Consolidation Methods for Compositionally and Microstructurally Graded Components

There exist many different routes to producing compositionally and microstructurally graded components. Many of these processing routes exploit the unique advantages of processing with powder materials. Specifically, the liquid-based additive manufacturing approaches (e.g., laser-based and electron-beam based) allow for a high degree of spatial control of the designed compositional variation where the local composition may be described as relatively homogeneous. Conversely, spark plasma sintering and HIP consolidation may be used when liquid-based processing would be detrimental to the microstructure. These methods will be discussed, with the advantages and limitations presented. They have been used to produce a range of Ti-based compositionally and microstructurally graded systems, including simple binary systems and more complex alloy variations. The effect of composition on the resulting microstructure will be presented, and the effect on local properties will be assessed.