Etch-Shadow Extraction Replica in Fracture Studies

Abstract

A new replica technique for electron microscopy of fracture surfaces is described, which can reveal the relationship between the microstructural features of metals and alloys and the detailed topography of their fracture surfaces. This etch-shadow extraction replica technique combines in one replica the salient features of shadowed-surface replicas and precipitate-extraction replicas. Thus a bridge is provided between the fracture topography, which is governed mainly by the effects of fracture-velocity changes, and the significant microstructural features such as precipitates, grain boundaries, etc.

Electron Microscopy

“…However, as new problems arise in connection with the study of the internal organization of consolidated materials, new replica techniques usually follow in the wake. For example, Banerjee, Hauser, and Cápenos (23), confronted with the problem of depicting the relationship between the microstructure of metals and alloys and the detailed topography of their fracture surfaces, developed a modified replica method. They review the commonly used replica methods which, although adequate for revealing the general fracture topography of metals, were found to be unsatisfactory for studying aspects of fracture initiation and propagation.…”

“…The microscopist is relying more on thinning methods than on replica methods for studying metals, although in fractography (23,440) replication is still the best method of approach for studying morphology unless one has access to a secondary emission microscope such as the Metioscope (38,486). For the removal of a disperse phase, such as precipitates, for subsequent diffraction studies, the extraction replica method has advantages.…”