TITLE:
Physical Nanoindentation: From Penetration Resistance to Phase-Transition Energies
AUTHORS:
Gerd Kaupp
KEYWORDS:
Energy Law Violation, ISO-14577 Challenge, Calculation Rules for Indentations, Phase-Transition Onset and Energy, Multiple Transitions, Safety Problems
JOURNAL NAME:
Advances in Materials Physics and Chemistry,
Vol.9 No.6,
June
28,
2019
ABSTRACT: -The ISO standard 14577 is challenged
for its violation of the energy law, its wrong relation of normal force FN with impression depth h, and for its iterative treatments. The solution
of this dilemma is the use of sacrosanct simplest calculation rules for
the loading parabola (now FN = kh3/2)
giving straight lines for cones, pyramids and
wedges. They provide the physical penetration resistance hardness k with
dimension [Nm-3/2] and allow for non-iterative calculations with
closed formulas, using simple undeniable calculation rules. The physically
correct FN versus h3/2 plot is universally
valid. It separates out the most common
surface effects and reveals gradients. It provides unmatched precision,
including reliability checks of experimental data. Regression analysis of FN versus h3/2 plots reveals eventual unsteadiness kink
phase-transition onset with the transition-energy. This is shown for all kinds
of solid materials, including salts, silicon, organics, polymers, composites,
and superalloys. Exothermic and endothermic single and consecutive multiple
phase-transitions with their surface dependence are distinguished and the
results compared in 5 Tables. The sharp phase-transition onsets and the
transition energies provide unprecedented most important materials’
characteristics that are indispensable for safety reasons. ISO ASTM is thus
urged to thoroughly revise ISO 14577 and to work out new standards for the
mechanically (also thermally) stressed materials. For example, the constancy of
the first phase-transition parameters must be controlled, and materials must
only be admitted for maximal forces well below the first phase-transition
onset. Such onset loads can now be easily calculated. The nevertheless repeated
oppositions against the physical analysis of indentations rest on incredibly
poor knowledge of basic mathematics, errors that are uncovered. The safety
aspects caused by the present unphysical materials’ parameters are discussed.