Determination of Coefficient for Transformation Plasticity in Terms of Three-Point Bending System

Abstract

To determine the transformation plasticity coefficient, a three-point bending system is employed and the large deflection due to transformation plasticity in bending is analyzed under the simplified assumption that transformations occur uniformly across the cross-section of a beam. It is shown that the deflection due to transformation plasticity is similar to that due to elastic deformation, and simple relationships are also derived between the ratio of the maximum deflection to the elastic deflection and material constants (transformation plasticity coefficient K and Young’s modulus E). Experiments are carried out for a slender bar specimen, which is loaded in a three-point bending system, and the austenized specimen is cooled so that martensite transformation accompanied by transformation plasticity occurs and the profile and maximum value of the deflection of the specimen are measured. The measured profiles of deflection agree very well with the theoretical results. This proves the validity of the proposed method. The transformation plasticity coefficient is also determined by the proposed method.