The Portevin-Le Chatelier Effect in Vanadium

Abstract In order to examine the temperature and strain-rate dependences of the Portevin-Le Chatelier (P-L) effect, tensile tests were carried out, using vanadium containing 170 p.p.m. of carbon and 42 p.p.m. of oxygen. The results obtained were as follows. 1. The P-L effect is observed in the temperature range from about 200°C to 500°C for a strain rate of 3.3 × 10−5/sec. 2. The serrations observed after the initial Luders strain are classified into two types, relatively fine serrations (Type A) and coarser serrations (Type B) which appear intermittently and are observed clearly in the higher temperature region. 3. Type A serration is associated with a very high work-hardening rate, while the rate is smaller with Type B serration. 4. In the lower temperature region, the P-L effect is observed only when the deformation proceeds beyond some critical strain, and the serration increases in stress amplitude with strain, while, in the higher temperature region, Type A serration disappears abruptly at some crit...