Reports of Current Research on Wear

INTRODUCTION

     Wear is unwanted material removal through a sliding movement of a solid over another.  Its effect is significant to the functions of many kinds of artificial and natural joining mechanisms.  The gradual removal of a material(s) from one or both surfaces in contact increases the clearance between the surfaces.  This spatial freedom induces a vibration that often leads to fatigue failures of machinery components.  In many cases, the presence of a wear product, wear debris, causes severe pain and leads to the failure of total hip or knee prostheses.  Therefore, a relatively small amount of material by wear can cause the failure of large and complex devices.

     There are many possible wear mechanisms; adhesion, abrasion, erosion, and so on.  Generally, more than a single mechanism occur at the same time.  However, there is always a primary mechanism that determines the material removal rate.  Whenever there is a possibility of abrasive wear, it is the most important problem to be solved.  The wear rate of abrasive wear is at least one to two orders of magnitude larger than those of other mechanisms. 


RESEARCH DESCRIPTION

     The wear properties of a monolithic silicon carbide and a ductile matrix composite are systematically investigated.

- Abrasive wear of a monolithic silicon carbide (3ABC-SiC) 
The microstructure of a hot pressed silicon carbide was changed by the following thermal exposure at a high temperature, above 1200 ^o C for 72 hrs.  The wear properties of the silicon carbide with different microstructures have been investigated by conducting two-body abrasive wear tests under different conditions.

- Abrasive wear of a multiphase material
Wear resistance of a multiphase material can be enhanced by introducing a secondary phase(s) into the matrix material.  In order to obtain optimum wear properties without compromising the beneficial properties in the matrix material, an accurate prediction of the wear of composites is essential.  A simple physically-based model for the abrasive wear of composite materials has been developed based on the mechanics and mechanism associated with sliding wear in soft (ductile) matrix composites containing hard (brittle) reinforcement particles.

Gun Y. Lee, C.K.H. Dharan, and R. O. Ritchie, " A Physically-Based Abrasive Wear Model for Composite Materials , Wear, 252 (2002) 322~331.

Abrasive Wear Behavior of Heat-Treated ABC-Silicon Carbide by X. F. Zhang, G. Y. Lee, Da Chen, R. O. Ritchie, and L. C. De Jonghe, Journal of the American Ceramic Society, vol 86 (8), 2003, pp. 1370-1378

RESEARCHERS
                                    Gun Y. Lee
                                    Xiao-Feng Zhang
                                    Robert. O. Ritchie
                                    Lutgard De Jonghe