深冷轧制制备纳米6061铝合金的热稳定性评估.pdfVIP

Trans. Nonferrous Met. Soc. China 27(2017) 754−762 Thermal stability evaluation of nanostructured Al6061 alloy produced by cryorolling M. ABBASI-BAHARANCHI, F. KARIMZADEH, M. H. ENAYATI Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111, Iran Received 2 January 2016; accepted 12 October 2016 Abstract: Grain growth of nanostructured Al6061 produced by cryorolling and aging process was investigated during isothermal heat treatment in 100−500 °C temperature range. Transmission electron microscopy (TEM) observations demonstrate that after cryorolling and aging at 130 °C for 30 h, the microstructure contains 61 nm grains with dispersed 50− 150 nm precipitates and 0.248% lattice strain. In addition, an increase in tensile strength up to 362 MPa because of formation of fine strengthening precipitation and nano-sized grains was observed. Thermal stability investigation within 100−500 °C temperature range showed release of lattice strain, dissolution of precipitates and grain growth. According to the X-ray diffraction (XRD) analysis, Mg Si 2 precipitates disappeared after annealing at temperatures higher than 300 °C. According to the results, due to the limited grain growth up to 200 °C, there would be little decrease in mechanical properties, but within 300−500 °C range, the grain growth, dissolution of strengthening precipitates and decrease in mechanical properties are remark