Measuring Interfacial Fracture Toughness With The Blister Test

1996 ◽  
Vol 436 ◽  
Author(s):  
R. J. Hohlfelder ◽  
H. Luo ◽  
J. J. Vlassak ◽  
C. E. D Chidsey ◽  
W. D. Nix
Keyword(s):  
Interface Crack ◽  
Crack Extension ◽  
Test System ◽  
Interfacial Fracture Toughness ◽  
Adhesion Promoter ◽  
Critical Crack ◽  
Blister Test ◽  
Crack Extension Force ◽  
Extension Force ◽  
Film Substrate

AbstractThe adhesion of thin films to substrates can be quantified using the blister test, which measures the crack extension force (G) required to propagate a crack along the film/substrate interface. We summarize the derivation of crack extension force for the blister test, and discuss how blister tests can be conducted by measuring only the pressure and volume of liquid injected into the test system. We describe a way to calculate the velocity of the interface crack front.Data from blister tests of acrylate films (14 μm thick) on nitride substrates are analyzed. The critical crack extension forces (GC) measured were 25 − 34 J/m2 for samples which had a commercial adhesion promoter at the interface, and 0.5 − 2.0 J/m2 without the adhesion promoter. GC was observed to increase with the velocity of the interface crack, and the dependence appears to obey a power-law.

Crack-Extension Force for a Part-Through Crack in a Plate

1962 ◽  
Vol 29 (4) ◽  
pp. 651-654 ◽  
Author(s):  
G. R. Irwin
Keyword(s):  
Stress Field ◽  
Crack Extension ◽  
Crack Opening ◽  
Elliptical Crack ◽  
Field Parameter ◽  
Experimental Measurements ◽  
Boundary Points ◽  
Crack Extension Force ◽  
Extension Force

The crack stress-field parameter K and crack-extension force G at boundary points of a flat elliptical crack may be derived from knowledge that normal tension produces an ellipsoidal crack opening. Rough correction procedures can be employed to adapt this result for application to a part-through crack in a plate subjected to tension. Experimental measurements suggest this adapted result has a useful range of accuracy.

Modeling of the Blister Test to Express Adhesive Strength in Terms of Measurable Quantities

1993 ◽  
Vol 308 ◽  
Author(s):  
Jim Sizemore ◽  
David A. Stevenson ◽  
John Stringer
Keyword(s):  
Adhesive Strength ◽  
Chemical Vapor ◽  
Absolute Measurement ◽  
Quantitative Information ◽  
Blister Test ◽  
Shape Models ◽  
Crack Extension Force ◽  
Chemical Vapor Deposited ◽  
Experimental Parameters ◽  
Extension Force

ABSTRACTThe adhesion of chemical vapor deposited (CVD) diamond thin films to substrates is a major limitation to using this new and exciting material. It is important to have a quantitative and absolute measurement of adhesive strength to understand and identify remedies. There are many methods to measure adhesion, but most rely on comparison to a standard instead of being an absolute measurement. The blister test is potentially able to measure adhesion both quantitatively and absolutely, but the existing analysis is not sufficient. This paper presents a fracture mechanics approach to analyze the blister test for a circular plate in order to obtain the appropriate quantitative information, i.e., the crack extension force, G. Several shape models exist. We consider several models to predict the behavior of this plate and then derive an equation that expresses G in terms of the critical pressure and critical volume at which de-bonding occurs. As a result of this analysis, we identify the key experimental parameters and show that this equation is insensitive to the model used.

A crack extension force correlation for hard materials

2007 ◽  
Vol 148 (2) ◽  
pp. 109-114 ◽  
Author(s):  
W. W. Gerberich ◽  
W. M. Mook ◽  
C. B. Carter ◽  
R. Ballarini
Keyword(s):  
Crack Extension ◽  
Hard Materials ◽  
Crack Extension Force ◽  
Extension Force

Energy balance concepts in the physics of fracture

1991 ◽  
Vol 435 (1893) ◽  
pp. 169-184 ◽  
Keyword(s):  
Energy Balance ◽  
Crack Growth ◽  
Crack Extension ◽  
Driving Forces ◽  
Second Law Of Thermodynamics ◽  
Crack Extension Force ◽  
Fracture Toughening ◽  
Extension Force ◽  
Definition Of ◽  
Energy Balances

It is pointed out that there are a number of incompatible energy balances used in the study of fracture and fracture toughening. The original Griffith theory is based on the second law of thermodynamics and in the framework of this law a cracked body is in unstable equilibrium when the appropriate thermodynamic potential reaches a maximum value. This energy balance allows the identification of both the thermodynamic driving forces for crack extension and the forces resisting crack growth. A second, and widely used, energy balance is based on the first law of thermodynamics which is simply one of energy conservation and can yield no information about crack instability without further assumptions. The two energy balances are considered in relation to the effect of energy dissipating processes on fracture. It is shown that a crack extension force cannot be defined by dividing the sum of all the energy increments arising from all the processes accompanying crack extension by the increment of crack area since this gives rise to paradoxical results. It is concluded that the energy changes brought about by processes such as plastic deformation which accompany crack extension should not be included in the definition of a crack extension force. A local energy balance is used to define a crack extension force which yields results identical to crack shielding calculations in fracture toughening studies. It is shown that the work done by energy dissipating processes per unit area of crack surface does not act to increase the crack resistance or the ‘effective surface energy’. Energy dissipating processes have their effect on fracture by virtue of the fact that they alter the state of stress around the crack tip and thus reduce the thermodynamic driving force for crack growth.

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