Short-time chemomechanical effects in lithium fluoride

Abstract

The apparent absence of environmental effects on dislocation mobility in crystalline non-metals as revealed by short time (∼1 sec) indentation tests, in contrast with the significant environmental effects observed in drilling and sliding friction studies, represents an important inconsistency in present understanding of chemomechanical effects. This anomaly has been resolved by studies of the environment-sensitive motion of edge dislocations introduced by micro-hardness identations into LiF monocrystals followed by subjection to a stress wave of ∼ 100 μsec duration propagating through the sample. Significant environment-sensitivity was noted, with near-surface dislocations moving substantially further when the specimens were exposed to dimethyl formamide compared with exposure to moist air.