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The Measurement of Total Inclusion Content in Nickel-Titanium Alloys

Frank Sczerzenie, Giorgio Vergani, and Clarence Belden

Submitted May 22, 2012; in revised form August 23, 2012

Inclusion content is important for the properties of high performance alloys used in fatigue rated devices. A method to analyze the total inclusion content of NiTi alloys was applied to vacuum induction melted vacuum arc remelted hot rolled coil and cold drawn wire. Carbides and oxides populations were analyzed separately. Pursuant to ASTM standards, a definition for stringers was formulated and applied to cold drawn wire. It was shown that changes in melting and hot working result in changes in the amount and size of carbides and oxide inclusions. The inclusion size distributions are highly skewed. It is hypothesized that the statistics of extreme values must be applied to these populations in order to predict a maximum inclusion size. Download the Full Article here.