New Characterization of Solid Materials and Anisotropy: An Approach towards Phase-Transition Energies
DOI:
https://doi.org/10.9734/bpi/mono/978-93-5547-921-1/CH7Keywords:
Instrumented Indentation, loading curve, phase transition onset and energy, iteration-less plot, physical exponent, present ISO standard, energy law violations, physical hardness, error detectionsAbstract
The detection of phase transitions under load and their transition energy is made possible by non-iterative analysis of the indentation findings. On the basis of the empirically based normal force depth3/2 relation, the closed algebraic equations have been derived. The precise transition onset position is obtained by linear regression of the FN = kh3/2 plot, where k is the penetration resistance, which also provides the axis cuts of both polymorphs of first order phase transitions. The phase changes can be endothermic or exothermic. They are normalized per \(\mu\)N or mN normal load. The validity of the loading curves, including those from calibration standards that display previously undiscovered phase-transitions and are thus unreliable, is checked using analyses of indentation loading curves with self-similar diamond indenters. The loading curves from instrument vendor handbooks are utilized to calculate the phase-transition energy for fused quartz. For the first time, the anisotropic behavior of phase transition energies is examined. A helpful test item is \(\alpha\)-quartz. On the basis of the local crystal structure under and surrounding the inserting tip, the causes of the packing-dependent changes are explained.
