Two methods of hardness determination for modern materials by an automatic indentation

 
E.Pechkovskiy,
  

I. M. Frantsevich Institute for Problems of Materials Science of the NAS of Ukraine, Krzhizhanovsky str., 3, Kyiv, 03142, Ukraine
Electron Microscopy and Strength of Materials - Kiev: Frantsevich Institute for Problems of Materials Science NASU, 2008, #15
http://www.materials.kiev.ua/article/315

Abstract

By method of an automatic indentation of various type and structural state materials (37 materials) it is established that the values of hardness determined by a technique of International Standard HIT=0,418 Fmax/hc2 and with use of work Wc, executed enclosed force Fmax on replacement by an indenter of a material in contact area of print HWc=0,125 Wc/hc3, not always coincide. Distinction between them ΔH=HIT - HWc grows in process of increase of values relative outcontact elastic deformation εes and hardness HIT of a material. On the basis of the received experimental data the explanation of this effect according to which presence of difference ΔH and its value are determined by elastic properties of a material, first of all - value relative outcontact is offered to elastic deformation εes of a material which, in turn, is defined by the contact modulus of elasticity E* and a structural state of a material. These three factors in aggregate supervise value of material hardness. By results of the analysis of dependence of absolute hardness values HIT and value of difference ΔH from values εes and HIT the investigated materials the map of structural states in coordinates es - HIT is constructed. The map contains 4 areas, in each of which materials with the certain type of a structural state, limits relative outcontact elastic deformation ε and levels of hardness settle down. The map allows identifying unknown structural state of a material.


AN AUTOMATIC INDENTATION, HARDNESS ON WORK, STANDARD HARDNESS, THE MAP OF STRUCTURAL STATES