INFLUENCE OF CREEP ON THE MICROSTRUCTURE OF ZN-AL-CU ALLOYS AGED AT 250-DEGREES-C

This paper is a continuation of a microstructural study of ZA alloys s ubjected to ageing at different temperatures with subsequent creep at 20 and 120 degrees C. It was already established that the samples aged for one week at 100 and 250 degrees C show the slowest creep rate. Fu rthermore, the results obtained after ageing at 250 degrees C are bett er than those obtained after ageing at 100 OC. In order to explain mor e correctly these results, the microstructure is studied after ageing al 250 degrees C and subsequent creep at room temperature under pressu re at 100 MPa and al 120 degrees C under pressure at 40 MPa, on test s amples broken after the respective creep.