Deformation of SS 304 LN during Scratch Test and Influence on Evolution of Coefficient of Friction

Satender Kataria,Sitaram Dash,Ashok Kumar Tyagi,Niranjan Kumar

doi:10.1155/2009/648075

Satender Kataria, Sitaram Dash + Show 2 more

Open Access

https://doi.org/10.1155/2009/648075

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Abstract

An AISI 304 LN nuclear grade forged, metallographically polished specimen was subjected to progressive load scratch tests using a spheroconical indenter at three different scratch speeds 1, 3, and 27 mm/min. The present study attempts to address the evolution of coefficient of friction with scratch speed invoking its correlation with scratch induced deformation in the specimen. At higher scratch speeds, plastic deformation rates were higher which caused friction coefficient to be of higher magnitude. This was correlated with dynamically obtained high resolution optical images that revealed deformation driven microstructural alterations. These alterations significantly influenced the evolution of friction coefficient which was intimately related to plasticity of the surface.

Highlights

The scratch test is a routinely used technique to measure the adhesive strength of coatings at the interface, but obtained results depend on many extrinsic and intrinsic parameters [1]
Less attention has been paid towards the study of deformation and evolution of coefficient of friction in case of bulk materials during progressive load scratch test
The plastic factor provides a scale of plastic deformation in the material

Summary

Introduction

The scratch test is a routinely used technique to measure the adhesive strength of coatings at the interface, but obtained results depend on many extrinsic and intrinsic parameters [1]. Results obtained from the scratch test depend on a number of parameters like scratch speed, scratch length, loading rate, surface roughness and material properties [1] These factors influence the evolution of coefficient of friction during scratch test [4]. The ratio between plastic and elastic deformation during a scratch test carried out with a Berkovich indenter is related to the ratio of elastic modulus to hardness of the specimen [8]. It is inferred from various studies [1, 3, 8– 10] that the role of friction in material characterization via indentation test is still a challenging field of research in applied mechanics. The resulting deformation and wear have been correlated with coefficient of friction

Experimental

Results and Discussion

Conclusions