Pergamon zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA NanaStructured Mataiak, Vol. 10. No. 5. pp. 111-793.1998 Elsevia Science Ltd PI1 SO96S-9773(98)00115-9 Q 1998 Acta M&allu@a Inc. Printedin the USA. All li8Ms resaved 096% 9773/98 $19.00 + .OO MECHANICAL AND TRIBOLOGICAL PROPERTIES OF NANOCRYSTALLINE AND NANOLAMINATED SURFACE COATINGS D.O. Northwood’ and A.T. Alpas tFac:ulty of Engineering and Applied Science, Ryerson Polytechnic University 350 Victoria St., Toronto, Ontario, Canada M5B 2K3 2Mechanical & Materials Engineering, University of Windsor Windsor, Ontario, Canada N9B 3P4 zyxwvutsrqponmlkjihgfedcbaZYXW (Accepted M ay 18,1998) Abstract- Themechanical and tribological Cfrictionlwear)properties were determinedfor nanocrystalline aluminum, as-sputtered Ti, Zr and Cufilms, and nanolaminatedAl-Alz03, Ti-nN, Ti- Cu and Ti- Zr zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA composite films. The aluminum grain size varied between IS and 106 nm. The Al and Ti layer thicknesses in Al-Al203 and Ti-TiN composites rangedfrom 70 to500 nm andfrom IS0 to 450 .nm, respectively. W ithin the grain size range of 15-100 nm, the hardness of the aluminum follows a Hall-Petch type relationship. The hardness of the Ti-TiN and Al-Ah03 films alsofollows a Hall-Perch relationship withthe Ti orA layer thickness. The Ti-Cu composites show a softening effect with decreasing Ti layer thickness. The coeflcient offriction and wear ratefor nanolaminated Ti-TiN and Al-Ah03 composites are consistently reduced as the metal layer thickness is reduced. The micromechanisms responsible for the differences in mechanical and tribological properties are examined and the results compared with published literature. 0 1998 Acta M etallurgica Inc. INTRODUCTION Some five years ago, we embarked on a long term research project entitled, “Development of Microlaminate Composites for Wear Resistant Coatings.” The objectives of this project were as follows: (i) to fabricate nano and microlaminate materials incorporating ductile metallic layers with reinforcing layers of non-metallic phases using a sputter deposition technique; (ii) to study the mechanical properties in order to identify the strengthening mechanisms which operate in the laminated composites and thereby develop improved materials by the exploitation of the strengthening components; (iii) to develop new methods for the assessment of tribological characteristics of these composites for potential wear resistant surface coating applications. In this paper we will summarize the achievements and main findings from this project and, where possible, compare the results with the published literature. Further details of some parts of this project can be found in our publications over the last five years (l-9). 777