Study on damage evaluation of bimetal with lead-free copper alloy (Application of Acoustic Emission method)

Abstract

The bimetal materials that sintered the powder of lead bronze on the base material (i.e. carbon steel) have the excellent performance as the bearing material. However, the nation or the society is moving on with the planning on the use restriction of lead and lead compound. Therefore, lead-free copper alloy is developed, and the practical applications of the alloy are advanced. However, the mechanical properties of the bimetal material that sintered the alloy powder have not sufficiently been grasped. In this study, the evaluation of the fracture mechanism and that types which arose in the materials was examined. As the results, it was possible to grasp or evaluate each fracture type by the frequency component of Acoustic Emission (AE) signal with Fast Fourier Transform (FFT) method, and the m value which is led from the amplitude distribution of the signal. By using the criterion for recognizing each type, it was proven that the proposed technique in this study can evaluate the fracture mechanism of each bimetal material which changed the type of the lining material.

Keywords

• material testing
• damage evaluation
• copper alloy
• sintered material
• acoustic emission