Initiation of an Interface Crack Under Mixed-Mode Loading

1993 ◽  
Vol 60 (1) ◽  
pp. 227-229 ◽  
Author(s):  
P. A. Foltyn ◽  
K. Ravi-Chandar
Keyword(s):  
Fracture Toughness ◽  
Interface Crack ◽  
Mixed Mode ◽  
Compact Tension ◽  
Model System ◽  
Mixed Mode Loading ◽  
Interfacial Fracture Toughness ◽  
Shear Specimen ◽  
Experimental Configuration

The compact tension shear specimen is proposed as a simple experimental configuration suitable for the determination of the variation of the interfacial fracture toughness as a function of the loading mixity. The suitability of this specimen is demonstrated on a model system of diffusion bonded PMMA.

Measurements of the Adhesion Strength of Cu/Epoxy Interfaces

1999 ◽  
Vol 586 ◽  
Author(s):  
H. Y. Lee ◽  
Jin Yu
Keyword(s):  
Fracture Toughness ◽  
Mixed Mode ◽  
Loading Condition ◽  
Double Cantilever Beam ◽  
Mixed Mode Loading ◽  
Interfacial Fracture Toughness ◽  
Brazil Nut ◽  
Molding Compound ◽  
Failure Path ◽  
In The Beginning

ABSTRACTCopper-based leadframe sheets were oxidized in a black-oxide forming solution, molded with epoxy molding compound (EMC), and the interfacial fracture toughness was measured using sandwiched double cantilever beam (SDCB) and sandwiched Brazil-nut (SBN) specimens.Results showed that pebble-like Cu2O precipitates on the leadframe had almost no adhesion to EMC while the opposite was true of the acicular CuO precipitates. Thus, the fracture toughness of the leadframe/EMC interface was close to zero in the beginning but rapidly increased to ˜100 J/m2 as acicular CuO nucleated on the smooth-faceted Cu2O layer. Under the mixed Mode loading the fracture toughness increased parabolically with the phase angle (ψ) with minimum at ψ = 0°. For ψ < -340, interface crack kinked into EMC. Fractography analyses based on XRD, SEM and AES studies showed that the failure path along the leadframe/EMC interface varied significantly with the loading condition and the crack speed.

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