THE EFFECT OF HYDROSTATIC PRESSURE ON THE TENSILE DEFORMATION OF SINGLE CRYSTALS

Journal Article · Sun Jun 01 04:00:00 EDT 1958 · Z. Metallk

OSTI ID:4331306

Haasen, P; Lawson, Jr, A W

The effect of 5000 atm pressure on the tensile stressstrain curve was investigated for single crystals of aluminum, copper, nickel, and alpha -brass as well as polycrystalline nickel. In all cases except nickel single crystals, the flow stress increases with pressure. The increase is larger than is expected from the change in the elastic moduli with pressure. Returning to deformation at 1 atm following a strain at 5000 atm the flow stress is still higher than normal. In pure metals the rise in flow stress under pressure is interpreted in terms of the work done against pressure to produce volume changes. The volume change due to plastic deformation is about 10/sup -4/. The residual increase in flow stress at 1 atun after deformation under pressure shows that the crystal work hardens more strongly under pressure in favor of a decreased volume production. These results are interpreted in terms of dislocation theory. An investigation on zinc single crystals shows that the hydrostatic pressure has no effect on deformation twinning. Twins thus are produced by the action of shear stresses only. A nucleation of twins at micro-cracks seems to be unlikely in this case since pressure strongly suppresses fracture in these crystals, but not twinning. (auth)

• Research Organization: Max-Planck-Institut fur Metallforschung, Stuttgart; Univ. of Chicago
• NSA Number: NSA-12-014055
• OSTI ID: 4331306
• Journal Information: Z. Metallk, Journal Name: Z. Metallk Vol. Vol: 49
• Country of Publication: Country unknown/Code not available
• Language: German

Related Subjects

ALLOTROPY
ALUMINUM
BRASS
BRASS-ALPHA
COLD WORKING
COPPER
COPPER ALLOYS
CRYSTALS
DEFECTS
DEFORMATION
ELASTICITY
HARDNESS
IMPURITIES
LATTICES
METALS
MONOCRYSTALS
NICKEL
PHASE DIAGRAMS
PHYSICS
PRESSURE
STRESSES
TWINNING
ZINC ALLOYS