POWDER METALLURGY METHODS FOR THE PRODUCTION OF FINE AND ULTRAFINE GRAIN TI AND TI ALLOYS

摘要

A process includes sintering hydrogenated titanium or titanium hydride (TiH2) and/or Ti metal in a dynamically controlled hydrogen atmosphere with hydrogen partial pressure greater than 0.01 atmosphere and at elevated temperature, to form a sintered titanium material; equilibrate the sintered material at an equilibration temperature below the sintering temperature and above the phase transformations including eutectoid decomposition temperature for an equilibration time sufficient for the hydrogen within the sample to reach equilibrium and homogenize the sintered titanium material; holding the sintered titanium material at a hold temperature below the temperature of sintering and a hold time sufficient for phase transformations including eutectoid decomposition of the sintered titanium material; and heating the sintered titanium material under vacuum, inert atmosphere, or a combination of both at a hold temperature which is less than that of the sintering temperature, to form titanium metal, or a titanium metal alloy with fine or ultrafine grain sizes; where the dynamically controlled hydrogen atmosphere varies as a function of time and temperature throughout the thermal cycle and includes hydrogen during the sintering and phase transformations including eutectoid decomposition steps.

主权项

1. A process for producing a sintered titanium material with fine grain size comprising:
sintering a particulate titanium feed material in a dynamically controlled hydrogen atmosphere at an elevated temperature to form a sintered titanium material containing hydrogen, wherein the particulate titanium feed material includes at least one of titanium metal (Ti) and hydrogenated titanium or Ti hydride (TiH2), and wherein the dynamically controlled hydrogen atmosphere comprises primarily hydrogen that was not produced from the particulate titanium feed material; and heating the sintered titanium material under vacuum or controlled inert atmosphere at a temperature which is less than the sintering temperature sufficient to remove hydrogen from the sintered titanium material.