Abstract: A test specimen is provided, that is constructed of dual materials, which are preferably metallic materials and which are more preferably an austenitic iron alloy and a ferritic iron alloy. The specimen is generally constructed as a rectangular configuration, with two principal legs, connected together by substantially rigid connections at their ends, with the legs being of the different materials, such that, when the specimen is subjected to heat, one leg will expand linearly an amount greater than the other leg allowing the imposition of bending stress, whereby a given leg will experience both tension and compression. Observation may then be made, by a microscopic examination or otherwise, of those surfaces that are adjacent the portions of the legs that experience most of the tension and compression, such that the effects of temperature on the materials may be observed and recorded.