Sub-Critical Crack Growth Parameters for Low Temperature Co-Fired Ceramic (LTCC)

Sub‐Critical Crack Growth Behavior of a Low‐Temperature Co‐Fired Ceramic

“…At equivalent risk of rupture, the relationship between the strength and effective volumes is where the σs and V s are the strengths and effective volumes in the respective tests. The Weibull modulus reported by Dannheim et al 9 is in the range of 7.8–8.2, and that reported by our group 10 is 8.78. Using an m value of 8.78 and a volume ratio of 318 in , the ratio of the strengths obtained in Dannheim et al 9 to those obtained here should be ∼1.92.…”

“…This is accomplished using the following steps: (1) the time to failure at a constant stressing rate ( t f,const.stress rate ) for each sample in the strength distribution is calculated by dividing the strength by the stressing rate, (2) the t f,const.stress rate is then converted to a time to failure at a constant applied stress, t f,const.stress using t f,const.stress = t f,const.stress rate /( n +1), (3) the failure stresses for the strength distribution are normalized to a fixed time to failure (say 1 s) using the relationship where σ is a constant applied stress, and (4) the failure probabilities are then calculated for increasing times using . The SPT diagram, using Weibull parameters obtained in our previous study 10 (characteristic strength=246 MPa, Weibull modulus=8.78) and using the n (=22.38) for the high‐RH environment, is shown in Fig. 5.…”

“…In Tandon et al , 10 the present authors presented preliminary results of the strength and SCG susceptibility for LTCC material tested in ring‐on‐ring (ROR) biaxial tension where a large area (>150 mm 2 ) was under maximum tension. Strength values ∼half of that reported in Dannheim et al 9 were obtained.…”

“…To the authors' knowledge, there are only four published studies on the mechanical behavior of the specific material (sintered DuPont™ 951 Green Tape™ (DuPont Microcircuit Materials, Towanda, PA), subsequently referred to as LTCC) of interest here 9–12 . Dannheim et al 9 analyzed the strength and SCG susceptibility of this material.…”

“…To the authors' knowledge, there are only four published studies on the mechanical behavior of the specific material (sintered DuPontt 951 Green Tapet (DuPont Microcircuit Materials, Towanda, PA), subsequently referred to as LTCC) of interest here. [9][10][11][12] Dannheim et al 9 analyzed the strength and SCG susceptibility of this material. The strength of small (B6 mm  6 mm  0.84 mm) samples was tested in a ball-on-ring (BOR) configuration over four orders of magnitude of stressing rate in an unspecified environment (probably ambient).…”