scholarly journals Properties of borided SAE 1035 steels and fracture toughness produced by Vickers indentation

2013 ◽  
Author(s):  
A. Kaouka ◽  
O. Allaoui ◽  
M. Keddam ◽  
S. Taktak
Keyword(s):  
Fracture Toughness ◽  
Vickers Indentation

The Influence of Some Technological Parameters on the Fracture Toughness of Ceramic Materials

2010 ◽  
Vol 446 ◽  
pp. 11-21
Author(s):  
Viorel Goanta ◽  
Marian Mares
Keyword(s):  
Fracture Toughness ◽  
Low Cost ◽  
High Hardness ◽  
Fem Analysis ◽  
Ceramic Materials ◽  
Indentation Load ◽  
Test Material ◽  
Vickers Indentation ◽  
Technological Parameters ◽  
Material Fracture

In order to determine the fracture toughness of the materials presenting high hardness values in the superficial layers, the Vickers micro-indentation was imposed as a reliable procedure. That method became attractive because of the relative simplicity of the experimental technique and because of its low cost. There are several calculus relationships that could be applied using the data provided by that method, in order to determine the material fracture toughness. The determination of fracture toughness using the Vickers indentation method is based on the analysis of radial cracks propagation, from the corners of the indentation trace. The length of these cracks is connected with the material fracture toughness, on the basis of some semi-empirical calculus relations that are taking into account the indentation load and some physical characteristics of the test material, as Young’s modulus and Poisson’s coefficient. In the present paper, fracture toughness was determined on a series of ceramic samples, made of the same material, but with different geometrical shapes and obtained by applying different technological procedures. The influence of some technological parameters on the fracture toughness was evaluated. The material fracture toughness was determined, into the vicinity of the propagated cracks (in a sample that could be a final product), on an area with a specified geometric contour. As a preliminary stage, a step by step FEM analysis was made, into the Vickers indentation material region, for different values of indentation load. In this manner, it was proved that the maximum stress value, on the perpendicular direction, as related to the crack diagonal plane, is always located at the peak of the indentation trace, and that is the effective start-point of cracking, for this type of indentation.

Fracture Toughness of HVOF Sprayed WC-Co Coatings

2000 ◽  
Author(s):  
S. De Palo ◽  
M. Mohanty ◽  
H. Marc-Charles ◽  
M. Dorfman
Keyword(s):  
Fracture Toughness ◽  
Gas Turbines ◽  
Wear Behavior ◽  
Physical And Mechanical Properties ◽  
Mean Free Path ◽  
Vickers Indentation ◽  
Centrifugal Pumps ◽  
Compressor Blades ◽  
Fracture Properties ◽  
Spray Process

Abstract Tungsten carbide-cobalt coatings are extensively used to protect surfaces from wear in many types of applications, such as compressor piston rods, pump plungers, shaft sleeves on centrifugal pumps and fans, and midspans of compressor blades in gas turbines. The wear behavior in any application is strongly influenced by the basic physical and mechanical properties of such coatings. Fracture toughness as a mechanical property indicates the resistance to fracture in the presence of a sharp crack, and thus provides a measure of the intrinsic strength of the cemented carbides coatings. In this study, Vickers indentation tests have been used to quantify the in-plane fracture behavior of various WC-based coatings deposited by the High Velocity Oxy-Fuel (HVOF) spray process. The indentation cracks are analyzed in terms of standardized relations that utilize radial-median crack geometries. It is shown that the fracture properties of HVOF WC-Co coatings are anisotropic, and depend strongly on the microstructure and composition of the coatings. The crack propagation is determined by the porosity, binder mean free path, and the shape, size, and distribution of the reinforcing carbide particles. The erosion resistances of the coatings have also been discussed as a function of the fracture properties and mechanisms. It is shown, in this study, that the Vickers indentation method is a useful and convenient technique for determining the in-plane fracture toughness of HVOF sprayed WC-based coatings.

scholarly journals Determination of fracture toughness using the area of micro-crack tracks left in brittle materials by Vickers indentation test

2013 ◽  
Vol 2 (1) ◽  
pp. 87-102 ◽  
Author(s):  
Alireza Moradkhani ◽  
Hamidreza Baharvandi ◽  
Mehdi Tajdari ◽  
Hamidreza Latifi ◽  
Jukka Martikainen
Keyword(s):  
Fracture Toughness ◽  
Brittle Materials ◽  
Indentation Test ◽  
Vickers Indentation
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