A novel technique for the fabrication of laboratory scale model functionally graded materials

In this work, the authors describe the design, fabrication and testing of m odel functionally graded materials (FGMs). The inhomogeneous property varia tions were generated by altering material properties through selective ultr aviolet (UV) irradiation. Poly(ethylene cc-carbon monoxide) (ECO) was chose n to make the FGMs because of its rapid degradation under UV light. irradia ted ECO becomes stiffer, stronger and more brittle with increasing irradiat ion time. Through a series of tension tests, the authors characterized the mechanical behavior of the specific ECO used as a function of UV exposure t ime. Furthermore, by controlling exposure time, specimens with continuously and discretely varying mechanical properties were produced. The resulting graded materials exhibited a Young's modulus that varied from about 160 MPa to 250 MPa and a strain to failure that varied from about 900 percent to 1 0 percent over the width in a 150 mm wide specimen. Microhardness measureme nts were used to determine the differences between discretely and continuou sly varying mechanical properties.