2009 Volume 27 Issue 2 Pages 115-123
The evaluation method for the microstructural stress-strain relationship of materials using a triangular pyramidal indenter is proposed in order to investigate the mechanical properties of steels and weld zone. An existing evaluation method using a ball indenter is correspondingly applied to the evaluation method using a triangular pyramidal indenter because the strain distribution under the indenter or the indentation curve on the unloading process between the ball and pyramidal indentation has a similarity. A corresponding ball indenter whose projection area is equal to that of the triangular pyramidal indenter is used to replace the triangular pyramidal indentation to the ball indentation, and the representative stress and strain that express the complicated deformation under the indenter are determined. The stress-strain relationships of single phase steels in microstructural size are estimated by the proposed method, and averagely correspond with those measured by macro-tensile tests. The difference of the stress-strain relationships due to the difference of the crystal orientation of each grain is possible to be negligible in this method. It is expected to clearly estimate the difference of the stress-strain relationship of each phase in such as dual phase steels by the proposed method.
