Spall strength of molybdenum single crystals

Abstract

Spall strength measurements for commerical grade molybdenum and molybdenum single crystals were made in a wide range of load durations (∼10−9 s – 10−6 s) and intensities (∼5 – 100 GPa). Resistance to fracture of pure single crystals was found to exceed two times the spall strength of polycrystalline molybdenum and to increase with shorter load duration. The value of the shock wave amplitude does not influence the spall strength of single crystals. The largest spall strength obtained under nanosecond load duration amounts to 30% of the ultimate theoretical strength.

Spall strength of niobium and molybdenum

“…Molybdenum displays a slight decrease in spall strength with increasing velocity, but in all cases is very low (<1 GPa), indicative of the brittle nature of the material. The values recorded here are slightly lower than those reported by Kanel [3], and the velocity-time histories he displays have a more pronounced reload signal. This may be due to a difference in material purity or processing routes affecting the ductility.…”

“…In order to gain an insight into the mechanical properties of the two materials in their pure form, gas gun plate impact tests were undertaken to determine the dynamic tensile (spall) strength over a range of impact stresses. Kanel, et al [3] investigated spall in molybdenum, using both single crystal and polycrystalline samples loaded explosively and with pulsed power techniques. He determined that spall strength was higher in the single crystal material, and that spall strength increased linearly with strain-rate.…”

Spall fracture: methodological aspects, mechanisms and governing factors

“…The values of spall strength in Fig. 12 were borrowed from Kanel et al (2001) for aluminum, Kanel et al (1992)and Tonks et al (2000) for copper, Kanel et al (1993) for molybdenum, Razorenov et al (2004) for iron, Parkhomenko and Utkin (1990) for organic glass (PMMA) and epoxy resin and Utkin et al (2004) for water. In Fig.…”

Mechanical Properties of Shock Treated Aluminium Alloy Al 2024-T4

“…The shock velocity D in the target corresponding to this particle velocity is obtained to be 5.73 km/s from the known Hugoniot of Al2024 alloy [10]. The Hugoniot elastic limit ( HEL σ ) and spall strength (σ s ) are determined from the free surface velocity profile using the following expressions [1,8,9]: E(GPa) Figure 1 The fringe shift recorded for S and P waves (top) and corresponding free surface velocity profile (bottom) determined from the fringe shift for Al2024-T4 alloy…”

“…The shock loading experiments are best suited for such studies, as, strain rates ranging from 10 3 /s -10 9 /s have been achieved in such experiments [1,2]. Further, the shock compression experiments designed properly can generate not only the high compressive stresses but also high tensile stresses in the materials [1][2][3] enabling to investigate material behaviour e.g. dynamic yield strength, spall fracture etc., in negative pressure regime also.…”