Flow and Fracture of Single Crystals

The elevated temperature tensile properties of S-200E commercially pure beryllium

“…Again, the shapes of the ductility vs. temperature curves are similar, but the 'elongations are consistently larger for the transverse orientation. This result is not surprising since the basal planes are more favorably oriented for the initiation and propagation of cleavage cracks in the longitudinal orientation [2,3]. The complex shape of the ef vs. temperature curves is believed to be associated with the natural increase in the fracture stress of the { 0001 } basal planes with increasing temperature [3] combined with hot shortness at intermediate temperatures caused by the presence of Al impurities, discussed below.…”

“…Further, since the mechanical properties of Be are known to be anisotropic [2,3], the tensile properties were evaluated for both the transverse and longitudinal orientations of the stock material. The results of these tests are presented in this report in such a way that the design engineer can make use of them in finite-element analyses.…”

Twinning and de-twinning in beryllium during strain path changes

“…Beryllium, in particular, primarily slips on the basal system, {00.2}/11.0S or, secondarily, on the prismatic system, {10.0} /11.0S [14][15][16]. Plastic deformation out of the basal plane must be accomplished by either pyramidal slip, {10.1}/11.3S, or twinning on the {10.2}/10.1S system.…”

Integrated X-ray substructure analysis of plastically deformed beryllium single crystals

“…The critical resolved shear stresses (CRSS) of the possible slip systems (table I) are extremely different [1]. Up to now most of the experimental investigations were carried out with cubic materials.…”