The mechanical properties of as-grown noncubic organic molecular crystals assessed by nanoindentation

摘要: Organic molecular crystals are often noncubic and contain significant steric hindrance within their structure to resist dislocation motion. Plastic deformation in these systems can be imparted during processing (tableting comminution of powders), the defect density impacts subsequent properties performance. This study measured elastic plastic representative monoclinic, orthorhombic, triclinic crystalline structures using nanoindentation as-grown sub-mm single crystals. The variation modulus due in-plane rotational orientation, relative a Berkovich tip, was approximately equal given crystal at fixed orientation. onset plasticity occurs consistently shear stresses between 1 5% all three systems, hardness ratio suggests conventional tips do not generate fully self-similar zones materials. provides guidance for mechanical models tableting, machining, property assessment