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Volume 6
Research & Reviews: Journal of Material Sciences
ISSN: 2321-6212
Advanced Materials 2018
September 04-06, 2018
Page 44
conference
series
.com
September 04-06, 2018 | Zürich, Switzerland
21
st
International Conference on
Advanced Materials & Nanotechnology
Gerd Kaupp, Res. Rev. J Mat. Sci. 2018, Volume 6
DOI: 10.4172/2321-6212-C3-020
On the way to physically correct indentation analyses
C
ommon indentation analyses (ISO and ASTM standardized) suffer from iterations, polynomials and approximations. However, correct
physics on the basis of elementary mathematics avoids iterations and violations of the energy law for hardness and modulus. The new
physically founded laws
F
N
=0.8
k h
3/2
and W
applied
/W
indent
=5/4 apply to nano, micro and macro depth sensing indentations. Importantly, they
detect phase changes under load and allow for the arithmetic treatment for single or successive phase transformations, surface layer effects and
correct adsorption energies. Thus, the first physical hardness H, stiffness/indentation moduli (these are not "Young's moduli"), indentation
works, activation energies and phase transformation energies are directly obtained, simply by application of the basic physically founded
equations that avoid the unfortunate common energy law violations. Non-steadiness kinks (in the linear
h
3/2
plots) and any deviations from
the precise 5/4 ratio (integration of the smooth appearing loading curves over one or more phase transition onsets is not allowed) prove phase
change (s) under load. For example, five successive phase changes to reveal six different polymorphs of NaCl up to 50 N load (corresponding
to HV5) from depth-sensing indentations will be presented and analysed. In addition to fcc and bcc, theoretical predictions published three
new polymorph structures and there is the possibility of twins and amorphous phases. The undeniable half-page physical deductions of the
two basic formulas will be presented and discussed as the derived formulas for the mentioned and further mechanical applications. This is not
only of academic interest, but materials' properties must be correctly and reliably described, and technical materials must withstand pressure
upon use without failing. The latter are at risk when phase change onset pressures remain undetected, because of the formed interfaces
between different polymorphs as sites for nucleation of cracks. Highly resolved (5000X) 3D-microscopy reveals details of crack nucleation.
The non-detection of of phase changes is the main objection against the reliability of non-depth-sensing Vickers, Brinell, Rockwell, etc.
hardness characterizations of daily life technical materials (not withstanding their always similar standard plates that equally undergo the
undetected phase changes). The neglecting of always several undetected phase changes misses the most relevant properties with creation of
high common risks. Furthermore, indentation measurements gain enormously in precision, because invalid single measurements can be
directly excluded when they do not concur with the undeniable physical
F
N
h
3/2
law's linear correlation with >3 or >4 nines, due to local
imperfections, or skew, or too close to interface or to borderline indentations. The safety issues also for all the numerous applications that
derive from ISO
H
and
E
r
are evident and largely unexplored.
Biograpy
Gerd Kaupp has completed his PhD at Würzburg University and Postdoctoral studies from Iowa State University, Lausanne University and Freiburg University. He held
a Full-Professorship till 2005 in Oldenburg, Germany and he privately continues his research on wasteless solid-state chemistry temperature-controlled with 100% yield
since 1984,AFM on rough surfaces since 1988, the non-stochastic but versatile and better resolving sub-diffraction limit microscopy for unstained non-fluorescing materials
of all types (resolution <10 nm, since 1995), and (nano) indentations (since 2000). In the latter field, he is still urging ISO (NIST) to correct their 50 years old standards for
conformity with physics. He has published more than 300 papers in renowned journals and has been serving as an Editorial Board Member of several scientific journals.
gerd.kaupp@uni-oldenburg.deGerd Kaupp
University of Oldenburg, Germany