Optimization of the sintering temperature, cooling time and grain size parameters to reduce residual stresses of copper-aluminum functionally graded material using response surface methodology

Abstract

One of the urgent needs for the medical, aerospace and military industries is to combine materials with heat-resistant as well as flexible structures. To create such a property, a ceramic must be placed next to metal. FGM materials have such a property in terms of thickness. Functionally graded materials (FGM) are examples of materials with different properties in the thickness direction. In the functionally graded materials, different properties can be created, by changing the percent weight of materials in each layer. It is very important to study the number of residual stresses in these materials due to the fact that several materials with different properties are combined with each other. The purpose of this study is to investigate the effect of production parameters on the number of residual stresses in the aluminum-copper FGM part and also to optimize the production process of these materials. The results indicate that the number of residual stresses decreases with increasing the sintering temperature, cooling time of the sample as well as uniformity along the thickness. In the experiments, the maximum residual stress was 171 MPa, which was obtained for a grain size of 100 microns, sintering temperature of 600°C and cooling time of 24 h and the minimum value of pressure residual stress was 120 MPa, which was obtained for grain size of 20 microns, sintering temperature of 900°C and cooling time of 48 h. Also, finite element modeling of the process was performed and shown a good agreement with experimental results.

Experimental study on tribological behavior of aluminum–copper functionally graded material

“…Gradual change in material properties across any geometrical direction resulted in the elimination of stress concentrations, fatigue, and corrosion. [1][2][3][4] FGMs withstand themselves in coarse environments without losing the characteristics of constituent elements and reduce their failure possibilities. Different material combinations, such as metal-ceramic, metalpolymer, ceramic-polymer, and metal-metal, having varied thermal expansion coefficients were developed as FGMs to attain different properties in a single component.…”

“…Few other works examined the acoustic impedance, residual stresses, and corrosion wear. 4,30,31 To the best of authors knowledge, no work was reported on tribological properties of Al-Cu FGM. Thus, present work is an attempt made to explore the erosion wear and abrasive wear behavior of Al-Cu MFGM fabricated through PM.…”