High temperature deformation and in situ fracture measurements to understand grain size/binder effects in hardmetals

该项目的目的是研究微观结构和粘结剂化学对裂纹扩展界面性能的作用。确定了构成材料的不同类型WC/WC晶界（就CSL而言）。人们正在围绕这些边界制造双悬臂梁（DCB），目的是了解界面特性。在WC单晶和大WC颗粒（~20-100微米）上进行了DCB测试，作为界面研究的基础：这将作为确定WC晶体平面表面能的机会，并与文献中的密度泛函理论计算进行比较。未来的工作将集中在研究WC/WC边界与钴渗透或铬层。WC/WC钴在蠕变过程中由于晶界滑动而发生渗透。添加铬是为了抑制晶粒生长。

The aim of the project is to examine the role of microstructure and binder chemistry on interface properties in crack growth. Different types of WC/WC grain boundaries (in terms of CSL) making up the material have been identified. Work is being done to fabricate double cantilever beams (DCB) around these boundaries with the objective of understanding interface properties. DCB tests have been performed on WC single crystals and large WC grains (~20-100 microm) as a basis for interface study: this is to be used as an opportunity to determine the surface energies of WC crystallographic planes and compare with density functional theory calculations from the literature. Future work will be concerned with studying WC/WC boundaries with cobalt infiltration or chromium layers. WC/WC cobalt infiltration occurs during creep due to grain boundary sliding. Chromium is added to inhabit grain growth.