Texture development and microstructure evolution in hot worked alumina

Yuechu Ma, Purdue University

Abstract

Numerical simulations of the texture development in hot worked alumina polycrystals have been conducted using the self-consistent and Taylor models. Based upon a close resemblance of both symmetries and intensities between simulated and experimental textures, it can be concluded that: (1) The textures primarily result from dislocation slip. (2) The self-consistent model is more applicable to a description of texture development in alumina or other ceramics where anisotropic yield surfaces and low crystal symmetries are common. To verify the results from models, the correlation between microstructural evolution and textures in hot worked alumina was investigated experimentally through a series of comparative experiments carefully designed to enhance or suppress certain deformation mechanisms. In this way, influences from each deformation mechanism were separated. The experimental results reveal that textures in hot worked alumina are not strongly dependent of grain morphology, and are insensitive to grain growth, indicating that both grain boundary sliding and recrystallization did not play a pivotal role in the texture development. Moreover, the experimental results further reveal that textures are produced from plastic deformation rather than green bodies preparation, and the presence of second reinforced phases in alumina can suppress the texture development. The results generated from this research offer a comprehensive physical picture of the texture development in hot worked alumina, allowing the conclusions to be further generalized to other ceramic systems as well.

Degree

Ph.D.

Advisors

Bowman, Purdue University.

Subject Area

Materials science

COinS