Apparatus for deformation tests of solids in liquid He-3

An apparatus for deformation of solids in liquid He-3 is constructed. Eithe r tensile deformation or compression of a specimen can be performed by exch anging the assemblies in the He-3 pot which has a capacity of about 30 cm(3 ). The pulling rod for transmitting load from the tensile testing machine t o the specimen runs inside the outlet tube of He-3, being isolated from He- 4 bath and almost free from mechanical friction. To measure the change in f low stress with the supernormal transition of superconducting metals, a sup erconducting magnet is mounted outside of the vacuum chamber which separate s the He-3 pot and the He-4 bath. Under an applied load for plastic deforma tion the system is stably operative down to 0.6 K, while the lowest tempera ture achieved is 0.5 K. Some results on Ta and NaCl are presented. (C) 2000 American Institute of Physics. [S0034-6748(00)03607-8].