Since the invention of the hardness test by Brinell around 1900 using a hard steel ball as an indenter and measuring the size of the residual indentation on a sheet of steel, the implementation of this test has is considerably diversified: use of diamond pyramids (Vickers, Knoop and Berkovich) and WC-Co cobalt bonded tungsten carbide balls, development of micro-hardness and nano-indentation machines, measurement of the force curve P-displacement during phases where penetration h of the indenter increases, then decreases (instrumented indentation test). These tests are performed on most materials: metal alloys, ceramics and polymers. The previous articles (see below) have presented the mechanical interpretation of the hardness test mainly in the case of metallic alloys, while specifying certain points relating to ceramics. Polymers are increasingly used as coatings in the automotive, mechanical and optical industries and most often only instrumented indentation tests are available to characterize their mechanical properties. The purpose of this article is to first present the main characteristics of the mechanical behavior of polymers, then to show how they can be determined from the results of instrumented indentation tests.
This article is the last in a series of five articles, the previous four are:
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body hardness and qualitative analysis [M 4 154] ;
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hardness of common metals. Rigid-plastic boundary case [M 4 155] ;
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material hardness. Influence of elasticity [M 4 156] ;
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body hardness. Analysis of other behaviors [M 4 157].
