Evaluation of Aging in Cast Heat-Resistant Alloys by Compression Testing

Mechanical properties of engineering materials are normally evaluated by means of tension testing due to the easiness to machine samples and calculate their properties. Unfortunately, samples made from castings are prone to failure due to the presence of mixed microstructures, porosity, and impurities, which limit their ductility and hinder testing. This work evaluates aging by means of compression testing in two heat-resisting alloys that were held at various times at high temperature. The procedure is based on the load-displacement curve that is converted into stress-strain by assuming constancy in volume and compensating for the effect of friction. The stress-strain data are fit into an exponential relationship from which the stresses for yield, saturation and that for the onset of necking in a tensile test would occur. The information from this procedure concurs with results obtained from tension tests and is used to assess aging in these alloys.