The Determination of Experimental Conditions of Continuous Indentation Test for Tensile Properties Evaluation at Elevated Temperature

摘要

High temperature mechanical properties, especially tensile properties, are basic data to determine safety and integrity of materials and structure used at the high operating temperature. High temperature tensile properties of materials and structures in use cannot be generally obtained from conventional tensile test. Continuous indentation technique has been researched as an alternative to conventional tensile test and optimum experimental conditions were reported for the continuous indentation testing at room temperature recently. In this study, optimum experimental conditions were suggested for the testing at elevated temperature. Especially, the parameters related to the time such as loading rate and holding time were given priority contrary to their negligible effects at room temperature. As a result, loading rate should be selected to enable to reflect the work-hardening characteristics of testing object. Since holding time is related to indentation creep phenomena causing the change of indentation load-displacement curve shape by load relaxation during holding at maximum load, it should be selected to enable to minimize load relaxation.