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Mechanical properties are the primary concern in the development and application of powder metallurgy (PM) titanium and its alloys. Their mechanical properties are reviewed by comparing PM with ingot metallurgy (IM) and by examining the dependence of the mechanical properties on the microstructures that are unique to PM titanium. The effects of the most critical factors (porosity, oxygen content, and microstructure) on mechanical properties are discussed. Throughout this review, PM Ti refers genetically to PM titanium and titanium alloys. IM Ti embraces ingot metallurgy titanium and titanium alloys. Static and dynamic properties are examined to illustrate the challenges as well as the opportunities for PM Ti. Selected recent PM Ti technologies and attendant mechanical properties are also assessed. [ABSTRACT FROM AUTHOR]

The conventional cold-compaction-and-sinter powder metallurgy (PM) approach offers an attractive solution to the near-net shape or preform fabrication of titanium and its alloys for cost reduction and/or improved chemical homogeneity and refined microstructures. However, the potential of the process is yet to be realized as a viable industrial approach. Kroll first compacted and sintered 14 titanium alloys in 1937, followed by significant efforts from DuPont during the formative years of the titanium industry in the U.S., and persistent efforts from many researchers thereafter. This article outlines a historical account of PM titanium and reviews the major characteristics of the approach for fabrication, including the mechanical properties obtainable from the process. Future directions to realize its commercial potential are recommended with respect to both currently available and emerging titanium powder products. [ABSTRACT FROM AUTHOR]

Titanium and its alloys have been in industrial use for over half a century; however, applications have been restricted primarily to the aerospace industry, where high strength and light weight are the most critical parameters, and to the chemical industry, where titanium's resistance to corrosion is the most critical parameter. Traditional titanium-production methods used to produce both titanium ingot and wrought products have inherently high manufacturing costs, due in part to the high affinity between titanium and its interstitial elements carbon, hydrogen, nitrogen, and oxygen. In contrast, the titanium-based powder metallurgy (PM) industry is still relatively young, and not only faces traditional issues with interstitial contamination, but also those associated with powder manufacturing and consolidation. The aim of this review is to document current titanium-powder-production methods and to examine newer continuous direct-powder-synthesis methods currently under development and expansion. [ABSTRACT FROM AUTHOR]

The metal powder injection molding process (MIM or PIM) has been applied to titanium in various forms since the late 1980s. Powder production is well advanced with many offerings, giving a wide choice in particle size, particle shape, purity, and cost. Likewise, component production steps exist with many variants, but a general baseline process is identified here. There is much knowledge on how to fabricate titanium using MIM, but this knowledge is concentrated in the hands of a few fabricators. Against this baseline, emerging innovations can be assessed. Demonstration products have been shown for several applications, including watch cases, toy trains, cell phones, heat valves, dental implants, and medical surgical tools. This article rationalizes the technical and economic factors to show why research efforts in titanium injection molding are focused on reduced interstitial contents. [ABSTRACT FROM AUTHOR]

An introduction to the Focus Issue of the journal is presented in which the editors discuss various reports within the issue on topics including the dynamic-fracture characteristics of injection-molded titanium materials, spark plasma sintering, and additive of manufacturing titanium alloys.

This section introduces a series of articles including production methods of powder metallurgy titanium, history of the sintering of titanium and titanium alloy powders, and mechanical properties of powder metallurgy titanium and their dependence on microstructure, porosity and oxygen content.