Initial Crack Extension in Two Intermediate-Strength Aluminum Alloys

1976 ◽  
Vol 98 (2) ◽  
pp. 152-158 ◽  
Author(s):  
C. A. Griffis ◽  
G. R. Yoder
Keyword(s):  
Aluminum Alloys ◽  
Crack Extension ◽  
Initial Crack ◽  
Thickness Variation ◽  
Linear Elastic ◽  
Geometry Dependence ◽  
Crack Movement ◽  
Resistance Curves ◽  
Point Bend

Three-point bend tests were conducted to examine the geometry dependence of JIc in two intermediate-strength aluminum alloys, 2024-T351 and 7005-T6351. The amounts of crack growth at selected points on the load-versus-deflection curves were delineated using a heat tinting technique. Resistance curves of J-versus-crack extension were constructed to facilitate determination of JIc at incipient crack movement. The through-thickness variation in fracture toughness of a 7.6-cm-thick plate of 7005 aluminum was determined and correlated with fractographic and metallographic observations. The current JIc measurements from subsized specimens of 7005 aluminum are compared with previous KIc characterizations using linear-elastic, full-thickness specimens.

A Simple Specimen for the Determination of Elastic-Plastic Fracture Mechanics Parameters on Hollow Cylinders

1989 ◽  
Vol 111 (3) ◽  
pp. 252-258
Author(s):  
E. Roos
Keyword(s):  
Fracture Mechanics ◽  
Linear Elastic ◽  
Arc Shape ◽  
Growth Laws ◽  
Resistance Curves ◽  
Hollow Cylinders ◽  
Elastic Fracture ◽  
Mechanics Characteristics ◽  
Crack Resistance Curves

Functions have been derived for a linear-elastic fracture mechanics specimen of an arc-shape, which because of this shape, can be removed relatively easily from pipes or cylindrical components. These specimens can be used for determining crack resistance curves using the J-integral so that, even for thinner components, it is relatively simple to obtain crack growth laws with crack propagation direction over the wall thickness. The ductile fracture mechanics characteristics determined on arc-shaped specimens corresponds well with the values determined on side-grooved CT-25 specimens.

Toughness determination of zirconia toughened alumina ceramics from growth of indentation-induced cracks

1996 ◽  
Vol 11 (12) ◽  
pp. 3057-3063 ◽  
Author(s):  
D. Basu ◽  
B. K. Sarkar
Keyword(s):  
Stress Intensity ◽  
Crack Extension ◽  
Polished Surface ◽  
Surface Cracks ◽  
Transformation Toughening ◽  
Alumina Ceramics ◽  
Bend Tests ◽  
Point Bend ◽  
Zirconia Toughened Alumina

Short surface cracks were generated by Vickers indentation on the polished surface of alumina and different zirconia toughened alumina (ZTA) specimens, and their morphology was studied by serial sectioning. These cracks were grown in three-point bend tests under stepwise loading, and variation of toughness with crack extension was plotted to graphically separate the contributions from residual stress intensity and applied stress intensity factors. The plateau toughness determined from the intercept height of the crack extension plots exhibited an upward trend with zirconia content up to 15 vol % ZrO2 addition in the composition, which was proportional to the fraction of transformable tetragonal grains contributing to transformation toughening.

Quantification the Effect of the Thickness of Thin Films on their Elastic Parameters

2011 ◽  
Vol 324 ◽  
pp. 93-96 ◽  
Author(s):  
Amel Gacem ◽  
A. Doghmane ◽  
Z. Hadjoub
Keyword(s):  
Thin Films ◽  
Elasticity Modulus ◽  
Calculation Model ◽  
Thickness Variation ◽  
Acoustic Signatures ◽  
Context Modelling ◽  
Universal Relationship ◽  
Film Substrate ◽  
Material Interaction

The determination of the characteristics and properties of thin films deposited on substrates is necessary in any device application in various fields. Adequate mechanical properties are highly required for the majority of surface waves and semiconductor devices. In this context, modelling the ultrasonic-material interaction, we present results of simulation curves of acoustic signatures for multiple thin film/substrate combinations. The results obtained on several structures (Al, SiO2, ZnO, Cu, AlN, SiC and Cr)/(Al2O3, Si, Cu or Quartz) showed a velocity dispersion of the Rayleigh wave as a function of layer thickness. The development of a theoretical calculation model based on the acoustic behaviour of these structures has enabled us to quantify the dispersive evolution (positive and negative) density. Thus, we have established a universal relationship describing the density-thickness variation. In addition, networks of dispersion curves, representing the evolution of elasticity modulus (Young and shear), were determined. These charts can be used to extract the influence of thickness of layers on the variation of elastic constants

Determination of Initial Crack Strength of Silicon Die Using Acoustic Emission Technique

2015 ◽  
Vol 44 (7) ◽  
pp. 2497-2506 ◽  
Author(s):  
Pei-Chi Chen ◽  
Yen-Fu Su ◽  
Shin-Yueh Yang ◽  
Steven Y. Liang ◽  
Kuo-Ning Chiang
Keyword(s):  
Acoustic Emission ◽  
Initial Crack ◽  
Acoustic Emission Technique

Determination of Fracture Toughness and K-R Curve for 2524-T3 Aluminum Alloy

2011 ◽  
Vol 291-294 ◽  
pp. 1039-1042
Author(s):  
Wei Xie ◽  
Shao Wei Tu ◽  
Qi Qing Huang ◽  
Ya Zhi Li
Keyword(s):  
Fracture Toughness ◽  
Aluminum Alloy ◽  
Stress Fracture ◽  
Test Data ◽  
Plane Stress ◽  
Crack Extension ◽  
Room Temperature ◽  
Mode I ◽  
Average Value

In the present work, the resistance to crack extension of 2524-T3 aluminum alloy under Mode I loading was studied by using the middle-cracked tension M (T) specimens. The curve, plane-stress fracture toughness and apparent plane-stress fracture toughness were calculated by test data. The average value of measured fracture toughness at room temperature was 161 MPam1/2. The results and conclusions can be referred in airplane skin design.

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