Abstract
Significant temperature rise occurs in specimen during mechanical tests at liquid helium temperature. We carried out measurements and an analysis of specimen temperature rise in order to get appropriate testing conditions during constant amplitude stress and strain cycling tests in liquid helium on typical austenitic stainless steels, titanium alloy and OFHC Cu. The magnitude of temperature rise increased with the increase of the test frequency and the strain range. The obtained testing conditions from specimen temperature measurements are as follows: i) In load-controlled fatigue tests, for tension-tension mode; less than 5Hz at a stress level of lower than yield strength and less than 1Hz at a stress level of higher than yield strength. For tension-compression mode; less than 1Hz at a stress level of lower than yield strength and less than 0.1Hz at a stress level of higher than yield strength, ii) In strain-controlled fatigue tests, less than 4×10-3s-1 at a higher strain level.
