Industrial High-load One-point Hardness and Depth Sensing Modulus

Abstract

The depth-sensing nano, micro, and macro instrumental hardness technique, which provides several additional mechanical parameters when using the proper force/depth curves exponent 3/2 on the depth of the loading curves, is compared to the physics of industrial single-point force indentation hardness measurements (Vickers, Knoop, Brinell, Rockwell, Shore, Leeb, and others). The equipment software usually calculates and displays most of the different types of macro hardness but not of the pristine material in favor of polymorphs due to mostly several consecutive phase transitions, to be only found by depth sensing indentations.  The ISO or ASTM standards do also not take into account the temperature dependent activation energy and phase change onset with phase-transition energy, which is vital information for applications of all sorts of solids. Only the latter reveal these, when not using the disproved exponent 2 on the depth h for the analysis. Furthermore, the high-load one-point approaches miss the inevitable stronger and more varied subsequent phase-transformations, leading to inaccurate interpretations of the properties of pristine materials. Examples are provided for the conversion of iterated ISO-hardness and finite element simulated hardness to physical hardness. The one-point procedures are still crucial for industry, but to ensure the accuracy of their conclusions, physical hardness and phase transition onset sequence detection must be added. That requires depth-sensing indentations and correct loading curve analysis. Multidirectional indentation moduli mix of (mostly) anisotropic materials without high-force depth-sensing equipment produce only faked Young’s moduli. For Young's moduli one needs tension, compression, or ultrasound techniques. Only these give reliable Young’s moduli for the multitude of mechanical parameters derived from them. Also, the iterated ISO indentation moduli must no longer be used for there-from calculated faked mechanical parameters.