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Dynamic strength of tungsten-rhenium alloys

: Tham, R.; Stilp, A.J.

DYMAT '92. 7th International Conference on Mechanical and Physical Behaviour of Materials under Dynamic Loading. Proceedings
International Conference on Mechanical and Physical Behaviour of Materials under Dynamic Loading <7, 1992, Saint-Louis>
Fraunhofer EMI ()
adiabatic shear band; adiabatisches Scherband; Bruchverhalten; dynamic material behavior; dynamisches Werkstoffverhalten; Fließgrenzenspannung; fracture mechanism; instrumented Taylor test; strain rate; Taylor-Test; tungston alloy; Verformungsgeschwindigkeit; Wolfram-Legierung; yield strength

W-Re-alloys having rhenium contents equal or smaller than 10 percent were tested under dynamic compressive loading, using the instrumented Taylor test method. The compression wave propagation was observed by means of strain gauges mounted at different locations along the surface of the test rods. Under quasi-static loading no defined yield point was observed, whereas, dynamic loading conditions revealed an elastic-plastic compression wave structure. The dynamic yield strength was determined as a function of the strain rate. For this purpose the measured value of compressive strain at the yield point and the given Young's modulus have been used. Up to a strain rate of 1500 1/s, only little influence of this parameter was found for each alloy. Higher strain rates resulted in a steep increase of the alloys strengths. For a strain rate of 3700 1/s, more then 40 percent strengthening compared to the static flow stress at 0.2 percent strain was found. The ductility of the materials under stu dy decreases under impact loading conditions. The dominant failure mechanisms are localization of plastic deformation within shearbands and forced brittle fracture.