Volume 13, Issue 3 (May 1985)
The Effect of Acoustic Impedance on the Apparent Impact Fracture Energy of a Tungsten Base Sintered Alloy
The effect of acoustic impedance on the apparent fracture energy of a sintered tungsten alloy, determined by impact testing was studied. Experimental results were analyzed utilizing the semi-empirical model proposed by Saxton et al, which relates inertial loading with materials acoustic impedance.
Inertial loading was found to have marked effect on the apparent impact fracture energy of the high acoustic impedance material (that is, a 93-W [nickel, iron] sintered alloy) used in this study. In contrast, no appreciable effect was observed for steel and aluminum alloys (lower acoustic impedance materials) tested for comparison. For the sintered tungsten alloy the work done by the inertial load is significant when compared with the actual fracture energy. Consequently, since the machine-indicated impact energy contains both contributions, the apparent energy values are significantly higher when compared with the corrected values for this material. It is recommended that control procedures aimed to both identify and reduce the role of inertial loads be used when fracture energy is determined by impact testing.