High speed rotating aircraft parts require high-strength metals such as titanium. Titanium nitride or oxynitride inclusions in titanium and titanium alloy parts lower strength, sometimes with disastrous results. The titanium nitride-oxynitride inclusions are also known in the industry as Type 1 hard alpha inclusions. Investigators have searched for the best means during various melting methods, for dissolving titanium nitride inclusions that may cause failure of high-speed, rotating, titanium alloy parts in jet engines. No accurate or quantitative means is presently available to determine the dissolution history of such inclusions. A large volume of work has been done on titanium nitride inclusions. While large, well-defined inclusions can be found by ultrasonic or radiographic (X-ray) means, there is presently no means of determining these inclusions if they are metallurgically continuous.
Those concerned with these and other problems recognize the need for an improved method for locating metallic nitride inclusions in metallic alloy ingots.