Tensile Failure of Tungsten Alloys

Abstract

Spall experiments were conducted on a 91W-Ni-Co and 93 W-Ni-Fe alloys. For the 91% W, the spall strength was 2.8 GPa. At 9GPa peak stress, the damage consists of isolated voids, and the failure starts mainly as grain cleavage. For the 93% alloy, the spall strength was 2.1-2.5 GPa. The results are very consistent with earlier measurements in which very rapid tensile failure was induced by transverse impact.

Recent Progress in Processing of Tungsten Heavy Alloys

“…Such behavior has been observed previously in other brittle materials [162]. Post mortem inspection of fully fractured (i.e., spalled) specimens would likely indicate both intergranular and cleavage mechanisms [138]. However, crack propagation and macroscopic spall behavior are thought to require substantial grain cleavage: once sufficiently large, a microcrack initiated along grain/phase boundaries will then propagate fully across the specimen, irrespective of the underlying microstructure.…”

“…WHAs such as the one studied here have been studied extensively, primarily as potential materials for KE projectiles [136]. Mechanical properties and physical phenomena at high strain rates have been obtained or observed using Hopkinson bar techniques [137], normal plate impact [138][139][140], and oblique flyer-plate impact [141]. In most of these, the bulk mechanical properties of the homogenized multiphase material (e.g., stress-strain curves and spall strengths) and microstructure such as fracture surfaces or shear localization initiation sites have been reported.…”

The effect of shock-wave profile on dynamic brittle failure

“…While the composite is known to fail in a brittle manner, it displays improved ductility under compression and tension in comparison to that of pure polycrystalline tungsten 18 . The shock response has been reported in the literature for pure polycrystalline tungsten [18][19][20][21][22][23][24][25][26] and tungsten heavy alloys [27][28][29][30][31][32][33][34][35][36] under different loading environments. For instance, in plate impact experiments using monolithic impactors, Zurek and Gray 18 reported spall strengths of WHA to be 3.4-3.8 GPa.…”

“…For instance, in plate impact experiments using monolithic impactors, Zurek and Gray 18 reported spall strengths of WHA to be 3.4-3.8 GPa. Dandekar and Weisgerber 30 reported the spall strength of WHA to be 1.7-2.0 GPa, whereas Bless and Chau 32,33 reported the spall strength for WHA to be 2.6 GPa. Vogler and Clayton 34 employed line-VISAR to spatially resolve statistics on the spall strength of WHA.…”