Akademik Veri Yönetim Sistemi
JOURNAL OF POLYTECHNIC-POLITEKNIK DERGISI, cilt.25, ss.871-877, 2022 (ESCI)
In structural applications where strength, i.e. strength to weight ratio is the primary requirement, iron-based materials must be replaced by materials with similar properties. Heat-treatable 7075 aluminum alloy is considered one of the common interests of researchers due to its strength similar to that of steels and is widely used in automobile, aircraft industry and marine applications. Besides its high hardness and strength, it is one of the most important alloys of the defense industry with its lightness. In this study, the changes that occurred during the retrogression and different re-aging (RRA) times on heat treatments of the commercially purchased T651 heat treated Al - Zn - Mg - Cu alloy were systematically evaluated. This heat treatment cycle; The first step of the RRA heat treatment, the retrogression process (re-solution), the samples are kept at 200 degrees C for 10 minutes and immediately cooled in water at room temperature and then in an argon atmosphere protected oven at 120 degrees C for 2-4-8-16-24-32 hours respectively. aging (re-aging) process has been completed with their application. SEM was used for microstructure studies and macro hardness measurement (HV1) of samples. EDS and map analysis were done and elemental distributions were observed. Micro strain values and the distance between planes were calculated by X-RD analysis.As the re-aging time of the sediments increased, their distribution increased. According to the results of the study, the maximum hardness value was seen in the material with RRA heat treatment for 24 hours.