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In this research, after pressing in a cylindrical mold, the AA 7075 alloy swarf was melted and cast in a wet sand mold. After rolling and cutting, sheets with two different thicknesses of 6 and 20 mm were obtained. The sheets after homogenization were solutionized at 485°C for 30 and 90 minutes, respectively, due to differences in thickness and thermal gradients. The solutionized samples were quenched in 3 polymer solutions containing 10, 30, and 50% Poly Alekylene Glycol. The results showed that melting, casting, rolling, and heat treatment of AA7075 alloy swarf similar properties to this alloy is achievable. Microstructural studies by optical microscopes (OM), Field Emission Scanning Electron Microscopy (FESEM), and X-ray diffraction (XRD) showed that by increasing the quenching rate after the solutionizing process, precipitation increases during aging. The tensile test results indicated that as the quench rate and internal energy increase, the diffusion driving force would increase the precipitation of alloying elements. Hence, this leads to an increase in hardness and reduction of its strain after aging.
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1. This study first aims to evaluate feasibility of recycling 7075 Aluminum Swarf and then assess the mechanical and microstructural properties of Recycled 7075 Aluminum Swarf.
2. After pressing in a cylindrical mold, the AA 7075 alloy swarf was melted and cast in a wet sand mold, in a controlled process to limits the defects and degassing.
4. non-aluminum elements such as impurities can be reduced by Martini N71P degasser tablets wrapped in aluminum foil and by holding it at the bottom of cast to complete the deoxidation and degassing process.
3. The sheets after homogenization were solutionized and aged at 485°C and at 121 ° C for 30-90 minutes and 24 hours, respectively.
5. The recycled 7075 aluminum alloys can be recovered, using swarf aluminum alloys as raw material. After homogenization, solutionizing and aging treatment, the recycled 7075 aluminum alloy have more uniform composition distribution, finer grain and better microstructure.
6. Microstructural and mechanical studies showed promising features regarding the recycling of AA 7075 swarf.
Type of Study:
Research Paper |
Subject:
Polymers