Design and Fabrication of Impression Creep Testing Setup and Experimental Validation with 2219Al Alloys

Abstract

Thermo-mechanical treatments are essentially performed on wrought heat-treatable metallic alloys, before final application as structural materials. High homologous temperatures are maintained while plastically deforming the alloys, to eliminate defects induced while casting. Many of these alloys are also exposed to high temperature applications, encountering creep failure mechanism. Hence, high temperature deformation and creep behavior of different materials is an area of increased interest, using different methodologies. The present research aims to design and fabricate a laboratory-scale experimental setup, to substitute commercial hi-end equipment, for high temperature impression creep testing. Heating arrangement for desired temperatures and provision for variable load application have been combined into one single desktop unit. Impression creep indentation on a material can be estimated, for various combinations of loads and temperatures, generating creep curves, homologous to conventional tensile creep tests. The functionality and compatibility of the setup were successfully validated by conducting impression creep experiments on 2219Al alloys, under varying conditions of loads and temperatures. The generated creep curves with three distinct creep stages, as well as creep rates, were analyzed with respect to time, and compared with the theoretical models. The individual influences of load and temperature on creep properties of the alloy were investigated. Different creep parameters of minimum creep rate, penetration depth, penetration velocity, stress exponent, and activation energy were further evaluated and successfully compared and correlated with the reported literatures.