Forming Behaviour of Additively Manufactured Al/Ti Material Compounds Produced by Cold Spraying

Cold spraying has great potential for additive manufacturing, especially of oxidation-sensitive metals, because the material is not melted and significantly higher deposition rates can be achieved than with conventional additive manufacturing processes such as selective laser melting or direct metal deposition. Titanium is regarded as a high-performance engineering material due to its unique combination of properties, including good corrosion resistance, biocompatibility and high strength at comparatively low density. However, due to its high price, it appears reasonable for many applications to use material compounds in which titanium is only used on the surface of the workpiece, while less expensive materials such as aluminum are used for the remaining volume. In the present work, cold sprayed pure titanium coatings were deposited on Al substrates and then formed to defined 3-dimensional final contours by die forging and rotary swaging. Different porosities were selectively set in order to evaluate their influence on the coating adhesion and cohesion in the forming process. Pre-consolidation of the coatings and the use of Al/Ti interlayers proved to be promising strategies.