He has been working in the areas of fatigue, fracture, nondestructive evaluation, and life-prediction methodologies of structural alloys and composites. Since joining UT, his research interests include mechanical behavior, nondestructive evaluation, biomaterials, and processing of high-temperature alloys and ceramic-matrix composites and coatings with the kind and great help of his colleagues at UT and the nearby Oak Ridge National Laboratory. He has published over five hundred papers, edited twenty books, and presented numerous invited talks at various national and international conferences.