Calculation of True Hardness Value of Zn added (BiPb)SrCaCuO Superconductor by Different Models

2015 ◽  
Vol 41 (1) ◽  
pp. 953-960 ◽  
Author(s):  
Ahmet Toplu ◽  
İbrahim Karaca ◽  
Uğur Kölemen
Keyword(s):  
True Hardness

Energy principle of indentation contact: The application to sapphire

1993 ◽  
Vol 8 (5) ◽  
pp. 1068-1078 ◽  
Author(s):  
Roman Nowak ◽  
Mototsugu Sakai
Keyword(s):  
Indentation Test ◽  
Shear Stresses ◽  
Anisotropic Behavior ◽  
Energy Principle ◽  
Triangular Pyramid ◽  
Indentation Tests ◽  
Crystallographic Planes ◽  
Continuous Indentation ◽  
True Hardness ◽  
Crystallographic Orientations

The recently developed energy principle of indentation mechanics was applied to the continuous indentation test performed on pure sapphire. Three crystallographic planes, M = (10$\overline 1$0), A = (1$\overline 1$10), and C = (0001), have been indented by a symmetrical triangular pyramid (Berkovich). The distinct anisotropic behavior of the indented crystal has been observed for the maximum indentation loads of 1.961 N, 0.686 N, and 0.392 N. The indentation hysteresis loop energy and the related “true hardness parameter” have been determined for various crystallographic orientations, as well as for two different orientations of the indenter. The observed effects have been discussed in terms of the energy principle of indentation with crystallographic considerations. The effective resolved shear stresses for the slip and twinning systems were calculated and applied to the anisotropic indentation behavior. It was concluded that the energy principle is highly recommended for analyzing the data of continuous indentation tests.

scholarly journals Revelation of a functional dependence of the sum of two uniaxial strengths/hardness on elastic work/total work of indentation

2006 ◽  
Vol 21 (4) ◽  
pp. 895-903 ◽  
Author(s):  
Dejun Ma ◽  
Taihua Zhang ◽  
Chung Wo Ong
Keyword(s):  
Functional Relationship ◽  
Functional Dependence ◽  
Indentation Test ◽  
Fatigue Tests ◽  
Total Work ◽  
Finite Element Analyses ◽  
Instrumented Indentation ◽  
The Relationship ◽  
True Hardness ◽  
Instrumented Indentation Test

Dimensional and finite element analyses were used to analyze the relationship between the mechanical properties and instrumented indentation response of materials. Results revealed the existence of a functional dependence of (engineering yield strength σE,y + engineering tensile strength σE,b)/Oliver & Pharr hardness on the ratio of reversible elastic work to total work obtained from an indentation test. The relationship links up the Oliver & Pharr hardness with the material strengths, although the Oliver & Pharr hardness may deviate from the true hardness when sinking in or piling up occurs. The functional relationship can further be used to estimate the sum σE,y + σE,b according to the data of an instrumented indentation test. The σE,y + σE,b value better reflects the strength of a material compared to the hardness value alone. The method was shown to be effective when applied to aluminum alloys. The relationship can further be used to estimate the fatigue limits, which are usually obtained from macroscopic fatigue tests in different modes.

scholarly journals Indentation Load-Size Effect in Al2O3 — SIC Nanocomposites

2010 ◽  
Vol 61 (5) ◽  
pp. 305-307 ◽  
Author(s):  
Erika CsehovAaA ◽  
Jana AndrejovskAaA ◽  
Apichart Limpichaipanit ◽  
Ján Dusza ◽  
Richard Todd
Keyword(s):  
Size Effect ◽  
Vickers Hardness ◽  
Indentation Load ◽  
Proportional Specimen Resistance ◽  
Load Size ◽  
Hardness Values ◽  
True Hardness

Indentation Load-Size Effect in Al2O3 — SIC Nanocomposites The indentation load-size effect (ISE) in Vickers hardness of Al2O3 and Al2O3 + SiC nanocomposites has been investigated and analysed using Meyer law, proportional specimen resistance (PSR) model and modified proportional specimen resistance (MPSR) model. The strongest ISE was found for alumina. Both the PSR and MPSR models described the ISE well, but the MPSR model resulted in slightly lower true hardness values for all materials investigated. No evidence of the effect of machining stresses on the ISE has been found.

scholarly journals A comparison of models for predicting the true hardness of thin films

2012 ◽  
Vol 524 ◽  
pp. 229-237 ◽  
Author(s):  
Alain Iost ◽  
Gildas Guillemot ◽  
Yann Rudermann ◽  
Maxence Bigerelle
Keyword(s):  
Thin Films ◽  
True Hardness

MECHANICAL PROPERTIES OF FERROELECTRIC CERAMIC NANOCOMPOSITES

2005 ◽  
Vol 04 (04) ◽  
pp. 607-613
Author(s):  
KWOK LUN LEE ◽  
AI KAH SOH ◽  
XIAO XING WANG ◽  
KIN WING KWOK
Keyword(s):  
Mechanical Properties ◽  
Indentation Size Effect ◽  
Ferroelectric Ceramic ◽  
Nano Particles ◽  
Compression Tests ◽  
Indentation Size ◽  
Depth Sensing ◽  
Reduced Modulus ◽  
Hardness Values ◽  
True Hardness

The micro- and nano-indentation techniques and compression tests were employed to determine the mechanical properties of PZT based composites dispersed with Al 2 O 3 nano-particles for comparison. Compared with the reduced modulus, the nano-hardness, which exhibited indentation size effect (ISE), seemed to be more sensitive to the indentation depth. The true hardness values were deduced, based on the modified proportional specimen resistance (PSR) model, from the depth sensing machine and micro-indenter. Both the micro- and nano-hardness of the nano-composites confirmed that the hardness was best improved by addition of 0.5wt% of Al 2 O 3.

scholarly journals Determination of Hardness and Fracture Toughness of Y-TZP Manufactured by Digital Light Processing through the Indentation Technique

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Ziyu Mei ◽  
Yuqing Lu ◽  
Yuxin Lou ◽  
Ping Yu ◽  
Manlin Sun ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Tetragonal Zirconia ◽  
Milling Process ◽  
Control Group ◽  
Digital Light Processing ◽  
Hardness Values ◽  
3D Printing Technique ◽  
True Hardness ◽  
Tetragonal Zirconia Polycrystal

Objective. The purpose of the study was to determine the hardness and fracture toughness of dental yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) manufactured by digital light processing (DLP) technology to study its clinical prospects. Methods. The experimental group was DLP-manufactured zirconia, and the control group was milled zirconia. The hardness was investigated under a range of test loads (0.49 N, 0.98 N, 1.96 N, 4.90 N, 9.81 N, 29.42 N, 49.03 N, 98.07 N, and 196.1 N). Meyer’s law was applied to describe the indentation size effect (ISE). Meanwhile, the PSR model and MPSR model were utilized to generate true hardness values. The cracks were observed to be induced by indentation under loads above 49.03 N, while the cracks showed the radial-median type under the load of 196.1 N, under which the fracture toughness was calculated. Results. The true hardness of DLP-manufactured zirconia was 1189 HV based on the PSR model and 1193 HV based on the MPSR model, a bit lower than that of milled zirconia. The fracture toughness was 3.43 ± 0.29   MPa √ m , which showed no statistical difference with the milled zirconia. Conclusion. The dental zirconia manufactured by the DLP 3D printing technique is similar to that manufactured by the conventional milling process in hardness and fracture toughness, thus having a promising future of clinical use.

scholarly journals A Method of Estimating True Hardness of Thinly Plated Metals

1956 ◽  
Vol 5 (34) ◽  
pp. 429-433
Author(s):  
Toshinori KURODA ◽  
Haruki KONDO
Keyword(s):  
True Hardness

Hardness Testing of Vulcanized Rubber. VIII. Hardness Tests with a Conical Indentor

1948 ◽  
Vol 21 (4) ◽  
pp. 926-928
Author(s):  
J. R. Scott
Keyword(s):  
Constant Load ◽  
Indentation Hardness ◽  
Square Root ◽  
Hardness Testing ◽  
Vulcanized Rubber ◽  
Hardness Tests ◽  
Sharp Point ◽  
Hardness Scale ◽  
Conical Form ◽  
True Hardness

Abstract The relation between load and depth of indentation for a conical indentor has been investigated. The theoretical relationship applicable to perfectly elastic materials (indentation proportional to square root of load) is found to hold for all the rubbers examined except one very hard sample, whose comparative inelasticity causes some deviation from this relationship. This result further confirms the correctness of the theoretical investigation on indentation hardness testing of rubber by indicating that the forces required to produce indentations of similar shape, but different sizes, are proportional to the squares of corresponding linear dimensions of the indentations. With a conical indentor under a constant load, the depth of indentation is approximately inversely proportional to the square root of the elastic modulus of the rubber at small elongations. A conical indentor is preferable to a ball indentor in that it shows more nearly uniform sensitivity to small differences in modulus (i.e., true hardness) at all parts of the hardness scale. It has previously been shown that the ball is superior to a flat-ended plunger in this respect. To approach still nearer to uniform sensitivity would presumably require a pointed indentor having a profile with concave sides. This would be difficult to make accurately, and very likely to damage on account of its sharp point; this might, indeed, be a disadvantage of the conical form also.

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