The Effect of Twins on the Mechanical Behavior of Boron Carbide

The microstructure and mechanical properties of boron carbide (B4C) samples processed by slip casting were compared with those processed by the conventional hot-pressing technique. Although the quasi-static and dynamic mechanical experiments showed comparable results between the slip-cast and hot-pressed B4C, scanning electron microscopy and electron backscattered diffraction of the B4C samples revealed significant differences in the microstructure. A notable difference was the numerous growth twins in the slip-cast samples. The twin planes were determined to be \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \left\{ { 10\bar{1} 1} \right\} $$\end{document} and consisted of 35 pct of the boundary population in the slip-cast B4C but only 1 pct of the boundary population in the hot-pressed B4C. It was hypothesized that the presence of twins will cause a different failure mechanism. The effect of the twins on the stress state was examined by finite-element simulations and will also be discussed.