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Volume 4
Nano Research & Applications
ISSN: 2471-9838
JOINT EVENT
October 04-05, 2018 Moscow, Russia
&
2
nd
Edition of International Conference on
26
th
International Conference on
Advanced Nanotechnology
Materials Technology and Manufacturing Innovations
Advanced Nanotechnology 2018
& Materials-Manufacturing 2018
October 04-05, 2018
Page 10
Gerd Kaupp
University of Oldenburg, Germany
Gerd Kaupp, Nano Res Appl 2018, Volume 4
DOI: 10.21767/2471-9838-C5-019
Basic physics disproves the obligatory ISO-14577 standards: A dilemma for all indentation
mechanics
M
ost mechanical properties of materials are deduced from indentation with pyramidal/conical diamond tips.
The obligatory ISO-14577 standard iterates hardness (H
ISO
) and elastic modulus (
E
r-ISO
) with triple violation
of basic physics (energy law violation, wrong exponent on
h
, and denying phase transitions under load). Very high-
load indentation techniques (Vickers, Knoop, Brinell, Rockwell, etc. hardness) are even more empiric and include the
same violations. Thus, the normal force (F
N
) is not proportional with
h
2
, but with
h
3/2
, as is physically founded
[4]
and
experimentally confirmed. The wrong exponent 2 also prevents the detection of initial surface effects (that must be
corrected for) and phase transitions under load. While the latter often occur within the 1000 µN range, some require the
mN and up to >25 N range, where multiple phase transitions generally occur with the additional risk of macroscopic
cracking (for example NaCl at 0.618 mN, 3.34 mN, 2.49 N, 9.12 N, 24.43 N, these without cracking
[13]
. The way for a
physical treatment of indentations has been paved with "Kaupp-plots" (F
N
=
k h
3/2
) since 1990. The material's penetration
resistance k requires the energy-law correction factor of 0.8. But that is still not appreciated by the establishment. And
pressure-formation requires work! Pressure has long been used for elastic modulus determinations though. It does not
help that the very high-force techniques rely on the diameters of the impression surface such as Vickers, Knoop, Brinell
(they are convertible into the depths), or that Rockwell and Shore measure the depth. Problems with cracks are not seen
and reported (this does not mean cracks upon unloading for fracture toughness), but different load ranges have to be
distinguished and empirical inter-conversion formulas are used. The physically valid
H
phys
=0.8k/tg
2
can now be obtained
by linear regression of the loading curve's Kaupp-plot, excluding the three flaws. Indentation moduli
E
r-phys
require
energy correction and experimental stiffness d
F
max
/d
h
, using simplest arithmetic. Indentation moduli are not the claimed
"Young's moduli" and should be directly calculated but not iterated with up to 11 free parameters. All of that is valid for
all types of materials and instrumented depth sensing techniques. The dilemma of the ISO standards against physics
and thus the woldwide "enforced” iteration of further wrong mechanical properties is detrimental, producing very
large size-dependend errors and increasing crack probabilities. Liability problems for disastrous material failures ensue.
Textbooks and instrument software must be rewritten, the ISO-14577, a NIST tutorial, and the opposing publications
retracted. The physical correctness must be installed for the sake of daily life security. Examples will be discussed. ISO
appears slow in changing its standards for complying with physics. I continuously ask them to release an urgent caveat,
telling that ISO-14577 will be subject to change for the physical reasons.
Recent Publications
1. Kaupp G, (2013) Penetration resistance: a new approach to the energetics of indentations. Scanning 35: 392-401.
2. Kaupp G (2013) Penetration Resistance and Penetrability in Pyramidal (Nano)Indentations. Scanning 35:
88-111