MICROHARDNESS ANISOTROPY IN CUBIC AND HEXAGONAL ZNS SINGLE CRYSTALS

Microhardness anisotropy of hexagonal and cubic ZnS crystals grown from the vapour-phase has been investigated. Experimental data have been analysed by statistical methods and it has been established that ZnS shows remarkable work-hardening. Whatever the crystal structure, on close-packed planes, it was not possible to observe microhardness anisotropy in different crystallographic directions (type A anisotropy). However, in both cubic and hexagonal crystals, on prism planes, type A anisotropy could often be seen. In both types of crystal, between the close packed and prism planes, a remarkable microhardness anisotropy could be measured on different planes (type B anisotropy). The value of this type B microhardness anisotropy was dependent on the degree of contamination of the crystal. On the basis of the measurements made it was established that the microhardness of ZnS follows the Meyer law. © 1969 Chapman and Hall.