Erwin Pink

Serrated flow in a ferritic stainless steel

Abstract The Portevin-Le Chatelier effect was analysed by measuring the stress drop Δσ. Russells assumption that Δσ depends on the aging process as described by Cottrell and Bilby was examined, but no agreement was found between the theory and the experimental results for a ferritic stainless steel.

Patterns of serrated flow in a low-carbon steel

A low-carbon steel was tested in tension. Varying the strain rates and the test temperatures within certain limits produced serrated stress-strain curves. A new finding is that the serrations exhibit all the same regular patterns as are encountered in tests with substitutional alloys.

Deformation mechanisms operating in a tungsten heavy alloy

Abstract The mechanical properties of a heavy metal with 92.5 wt.% tungsten were investigated in tension. The behaviour below 400 °C resembles that of b.c.c. metals, yet in details it deviates from the double-kink theory. Between 450 and 650 °C, a strength peak appears caused by dynamic strain aging of tungsten, accompanied by negative strain-rate sensitivities and serrated flow. Above 650 °C, strength and elongation deteriorate rapidly due to binder properties.

Features of the Portevin-Le Chatelier effect in a low-carbon steel

In the decades after the discovery of the Portevin-Le Chatelier effect, much attention was paid to defining the various types of serrations which appear under different test-temperature or strain-rate conditions. Such efforts were almost exclusively restricted to describing the features of stress-strain curves of f.c.c. alloys. Reports on serration types and their properties in b.c.c. alloy systems are rare and, when they exist, lacking in detail. Serrations appearing in tests with steels have apparently been considered as rather irregular and, therefore, inaccessible for a systematic evaluation. This paper is the first to report on the authors results for a low-carbon steel. It will demonstrate that almost all of the features of serrated flow, which have in the past been found in substitutional alloys, are equally well exhibited in an interstitial alloy.

Temperature-dependent deformation and fracture characteristics of a tungsten heavy metal

Abstract The mechanical properties of a heavy metal with 92.5 wt.% tungsten were investigated in tension. Three regions of distinct deformation characteristics exist. The low-temperature behaviour (