(Color online) Partial cross section of the sapphire-anvil cell for small-angle neutron scattering experiments. C: steady cylinder; P: piston supporting the moving anvil; Sa: sapphire anvil; G: gasket; S: anvil seat; PM: piston of the pressure intensifier; C-PM: cylinder housing the piston PM; Po-W: port for pressurized water; Po-N: port for pressurized nitrogen. The thickness of the gasket is between 1 and 3 mm and the central hole is 4–10 mm diameter. Notice the bore machined in the pistons PM and P, that allows the collimated neutron beam to cross the cell along its axis. With a neutron beam diameter of 7 mm the maximum forward scattering angle is . The incoming neutron beam is from right to left, as indicated by the arrow.
(Color online) Disassembled anvil cell showing, on the left, the cylinder C housing the piston P that holds the moving anvil, and, on the right, the cylinder C-PM housing the pressure intensifier PM. The two parts are held together by M10 bolts. In the foreground, the sapphire anvils are shown with their centering rings. The diameter of the anvil body is 30 mm and the thickness is 20 mm. The diameter of the anvil face is 14 mm.
(Color online) Anvil cell aligned parallel to the neutron beam and positioned in front of the SANS detector window on the left. The neutron beam runs from right to left. Notice on top of the cell the displacement transducer that measures the relative position between the two anvils. The overall length of the cell is .
(Color online) Typical fracture pattern of the sapphire anvils. Notice the circumferential crack at the surface of the anvil face that propagates with an angle of about 20° with respect to the normal of the face. An additional five to six radial fractures run across the thickness of the sapphire anvil. The anvil body and the anvil face are 30 and 14 mm in diameter, respectively. The thickness of the anvil is 20 mm. Single-crystal sapphire is grown according to the Czochralsky or Bagdasarov method.
Axial load, , as a function of the relative displacement, , between the two sapphire anvils. The zero of corresponds to the contact position of the anvils against the gasket. Symbols: (엯) unhardened Cu–Be gasket with initial thickness ; (◻) 316-SS gasket, ; (◇) 316-SS gasket, . The full lines are guides for the eye. The closed symbols correspond to the unloading stage of the gasket. Notice the residual plastic deformation of the 316-SS gasket that is larger than the Cu–Be one. The gasket hole is 10 mm in diameter and is filled with water. The anvil face is 14 mm in diameter.
Shift of the wavelength, , of the fluorescence line of a :SrFCl crystal as a function of the relative displacement, , of the anvils. . A 2-mm-thick 316-SS gasket is used. The external gasket diameter and the hole diameter are 26 and 10 mm, respectively. Gasket hole filled with: (엯) water; (◻) carbontetrachloride; (◇) bromobenzene. The sharp decrease of the fluorescence line is due to the crystallization of the sample. Measurements were performed at 20 °C.
Pressure, , determined from the shift of the :SrFCl fluorescence line as a function of the pressure, , computed from the sample volume variation (see the text). A 2-mm-thick 316-SS gasket with a 26 mm outer diameter and a 10 mm hole diameter is used. Sample cavity filled with: (엯) water; (◻) carbontetrachloride; (◇) bromobenzene. The initial anvil displacement required to ensure a tight sealing between the gasket and the sapphire anvils is subtracted from the anvil displacement . The thick long-dashed line represents the ideal pressure increase that would be observed without any radial extrusion of the gasket hole.
Normalized incoherent scattered intensity, , of a 50% –50% mixture contained in a 2- mm-thick 316-SS gasket, as a function of the wave-number transfer, . The external gasket diameter and the hole diameter are 26 and 10 mm, respectively. Sample pressure: (◻) 230 MPa; (◇) 330 MPa.
(a) Normal stress, , measured at the surface gasket as a function of the radius, , for increasing sample pressure values. Symbols: (엯) 0 MPa; (◻) 91 MPa; (◇) 200 MPa; (▵) 327 MPa; (◁) 400 MPa; (▷) 409 MPa. The gasket is made from a 61% Cu–25% Ni alloy. The gasket thickness is 1.8 mm and the central hole is 6 mm diameter. The diameter of the anvil face is 14 mm. Sample is water. is estimated from the shift of the :SrFCl fluorescence line from tiny crystals glued on one side of the gasket. The full lines are a guide for the eye. (b) Sample pressure, , computed from the shift of the :SrFCl fluorescence line as a function of the gasket squeezing, . Notice the almost linear pressure increment as a function of that shows that the hole diameter remains constant during the gasket squeezing up to about 300 MPa (see the text).
Normal stress, , as a function of the radius, , for decreasing sample pressures. Symbols: (엯) 391 MPa; (◻) 382 MPa; (◇) 364 MPa; (▵) 246 MPa; (◁) 191 MPa; (▷) 91 MPa. Same experimental conditions as in Fig. 9(a).
Pressure, , computed from the shift of the :SrFCl fluorescence line as a function of the gasket squeezing, . The sample fluid is water. (a) 316-SS gasket. The external diameter of the gasket and the hole diameter are 26 and 10 mm, respectively. The gasket thickness is: (엯) 1.0 mm; (◻) 2.0 mm; (◇) 3.5 mm. The shift to the right of the curve labeled with diamonds is due to some initial leaking between the sapphire faces and the gasket. (b) Unhardened Cu–Be gasket. Same gasket dimensions as in (a), but with thickness values: (엯) 1.0 mm; (◻) 1.5 mm; (◇) 2.0 mm.
Pressure, , of a water sample as a function of the normalized gasket squeezing, . Different gaskets machined from the same 316-SS rod are used. The initial thickness of the gaskets is . The external diameter of the gasket and the hole diameter are 26 and 10 mm, respectively. Notice the good reproducibility of the data.
Pressure, , computed from the shift of the :SrFCl fluorescence line as a function of the gasket squeezing, . Gasket made from annealed 61% Cu–25% Ni alloy with hardness value , and hole diameter : (엯) 4 mm, (◻) 6 mm, and (◇) 10 mm; : (◁) . Gasket made from annealed 54% Cu–25% Ni alloy with hardness value and , (▵). The initial thickness of the gasket is , except for the gasket labeled by (◁) with . Sample is water.
Vickers hardness, , of different gasket alloys. AP1D and AP4 alloys were annealed at 800 or 700 °C during . Cu–Be is unhardened at 280 °C during .
Article metrics loading...
Full text loading...