F. Derguti

Selection of steels suitable for additive layer manufacturing

Abstract There is an increased demand for specialist metallic powders driven by the growing use of various additive layer manufacturing (ALM) techniques. Currently, there are only a few steel grades available for these processes, but this technical note outlines a methodology for the selection of steel alloys suitable for the application of ALM, the aim of providing guidance on which steels would be worthy of further investigation as potential candidates for powder production.

Metal Injection Moulding of Low Interstitial Titanium

Metal injection molding (MIM) is a well-established, cost-effective method of fabricating small-to-moderate size near net-shape metal components. In the MIM of titanium (Ti), one of the key points in the process is the interstitial contamination, especially oxygen. This study examines the sources of interstitial contamination during the metal injection moulding of commercially pure (CP-Ti) and Ti6Al4V (Ti-64) alloys. Also presented is a route to control and minimize the contamination in the sintered parts. The effect of the levels of oxygen contamination on the mechanical parts is also presented in the work.

Continuous extrusion of a commercially pure titanium powder via the Conform process

It is shown for the first time that cold commercially pure titanium powder can be extruded through a standard Conform machine into fully dense wire with a fine recrystallised microstructure. The grain size has been shown to decrease with increasing wheel speed with an associated increase in tensile strength. The macrostructure of the wire extrudate exhibits a characteristic flow pattern with several regions defined by differences in average grain size and distribution. Finite-element modelling of the process shows the formation of the characteristic macrostructure from powder fed Conform. The process is continuous, utilises standard equipment and does not require powder preheating or inert gas shrouding providing a footing for a true cost reduction in long-section titanium mill product.