Feature article: PIM International, Vol.1 No. 1 March 2007, pages 27-32, 2073 words

Author: Dr David Whittaker, DW Associates, UK 

DW Associates, 231 Coalway Road, Wolverhampton, WV3 7NG, United Kingdom

Introduction

Dr David Whittaker reviews the MIM Titanium Workshop held at the EURO PM2006 Conference in Ghent, October 2006. The conference was organised by the European Powder Metallurgy Association (EPMA).

The unique properties of titanium (e.g. low density, high specific strength, good corrosion and oxidation resistance and excellent bio-compatibility) have been recognised for many years and titanium materials are used extensively in aircraft, chemical processing and medical applications.

Applications, however, are limited by the high costs of titanium products. The high costs are partially related to the very high material wastage associated with conventional wrought and machined products e.g. many aerospace applications involve the removal by machining of over 90% of the starting material. Machining costs are also high with this difficult-to-machine material.

Processing by powder metallurgy (PM) routes has the potential to attack these cost impediments; hence the rapidly expanding interest in titanium PM in recent years. So, within its programme of special interest workshops at its annual conferences, the European Powder Metallurgy Association (EPMA) has sought to address opportunities in this emerging field.

At Prague in October 2005, the Workshop addressed titanium PM in general, whereas the workshop in Ghent in October 2006 was specifically focussed on metal injection moulding (MIM) of titanium. Both of these Workshops were sponsored by the UK-based PowdermatriX Faraday Partnership.

PowdermatriX is one of a number of UK Government-funded Faraday Partnerships and is now an integral part of the more recently introduced Materials Knowledge Transfer Network. Its aim is to improve the competitiveness of UK companies in the advanced ceramics, PM, magnetic materials and hardmetals sectors. The partnership is building a network of industry, trade associations, research organisations and universities to provide these sectors with focused technology, research and training. To date around 200 organisations have become members.

Titanium PM has emerged as a leading theme, with widespread interest among the PowdermatriX membership. PowdermatriX has been active in stimulating and co-ordinating the PM titanium activity in the UK and hosted a conference, which attracted over 80 delegates, in 2004 at the School of Jewellery in Birmingham (1). This conference reviewed current developments in titanium powder production methods and consolidation technologies and highlighted opportunities in a range of industry sectors....

Further sections of this article include:

- Challenges ahead for injection moulding of titanium
- Creating markets for MIM titanium
- The influence of oxygen content

Figures and Tables:

Fig. 1 Cost breakdown of 25 mm Ti alloy plate (Courtesy of QinetiQ plc)

Fig. 2 Growth in Titanium usage in Boeing airframes (Courtesy of QinetiQ plc)

Fig. 3 Oxygen absorption by Titanium (Courtesy of QinetiQ plc)

Fig. 4 Oxygen content vs. tensile elongation – Published data on MIM Ti-6-4, density 95.5-96.7% (Courtesy of QinetiQ plc)

Fig. 5 TiJet MIM process route (Courtesy of TiJet Medizintechnik GmbH)

Fig. 6 Long-term implant application (Courtesy of TiJet Medizintechnik GmbH)

Fig. 7 Reshaping of brown part (Courtesy of TiJet Medizintechnik GmbH)

Fig. 8 Joining by sintering – hollow engine valve Case Study (Courtesy of TiJet Medizintechnik GmbH)

Fig. 9 Prototyping for heart valve prosthesis (Courtesy of TiJet Medizintechnik GmbH)

Fig. 10 Contamination level in sintered MIM CP Titanium products as function of the percentage replacement by titanium hydride powder of titanium grade 1 (Courtesy of Fraunhofer IFAM)