The Role of Stacking Fault Energy and Deformation Twinning on the Indentation Size Effect of FCC Pure Metals and Alloys

摘要

The effect of interfacial phenomena including the stacking fault energy (SFE) and twinnability, on the magnitude of indentation size effect of several FCC metals was investigated using nanoindentation. The hardness was measured using an XP nanoindenter with a high load attachment capable of producing loads up to 1 N using a single Berkovich tip. The materials included pure polycrystalline aluminum, nickel, silver, and alloys; 70/30 copper zinc (a-brass). The plastic deformation of FCC metals is influenced by two competing mechanisms, dislocation slip and deformation twinning. The SFE is the most important interfacial characteristic and affects the deformation of FCC metals due to its influence on dislocation cross slip and dynamic recovery. The influence of deformation twinning is thought to affect the ISE given a twin boundary can disrupt the movement of dislocations.