Superplastic Behavior of Al-4.5Mg-0.46Mn-0.44Sc Alloy Sheet Produced by a Conventional Rolling Process

Abstract

This article describes the superplastic behavior of the Al-4.5Mg-0.46Mn-0.44Sc alloy. The investigated alloy was produced by casting and was conventionally processed to form a sheet with a thickness of 1.9 mm and an average grain size of 11 lm. The superplastic properties of the alloy were investigated using a uniaxial tensile testing with a constant cross-head speed and with a constant strain rate in the range 1 3 10 24 to 5 3 10 22 s 21 at temperatures from 390 to 550°C. The investigations included determinations of the truestress, true-strain characteristics, the maximum elongations to failure, the strain-rate sensitivity index m, and the microstructure of the alloy. The m-values determined with the strain-rate jump test varied from 0.35 to 0.70 in the temperature interval from 390 to 550°C and strain rates up to 2 3 10 22 s 21 . The m-values decreased with increased strain during pulling. The elongations to failure were in accordance with the m-values. They increased with the temperature and were over 1000%, up to 1 3 10 23 s 21 at 480°C and up to 1 3 10 22 s 21 at 550°C. A maximum elongation of 1969% was achieved at an initial strain rate of 5 3 10 23 s 21 and 550°C. The results show that the addition of about 0.4 wt.% of Sc to the standard Al-Mg-Mn alloy, fabricated by a conventional manufacturing route, including hot and cold rolling with subsequent recrystallization annealing, results in good superplastic ductility.

An examination of the superplastic characteristics of Al–Mg–Sc alloys after processing

“…(1), the temperature and grain size compensated strain rate was plotted against the normalized stress as shown in Fig. 4 for results obtained without processing by SPD as listed in Table 1 [32][33][34][35][36][37][39][40][41][42][43][44][45][46][47][48], in Fig. 5 for results obtained after ECAP as listed in First, all of the results are mutually consistent.…”

“…First, it is important to recognize that there are numerous reports of superplasticity in Al-Mg-Sc alloys even without processing using SPD procedures. These results are summarized in Table 1 [32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48] and they cover various metal-working procedures based primarily on cold-or hot-rolling. Typically, the grain sizes in these materials are in the conventional superplastic range of ~1 -10 µm.…”

“…FIG.4Temperature and grain size compensated strain rate versus normalized stress for various superplastic Al-Mg-Sc alloys without SPD processing[32][33][34][35][36][37][39][40][41][42][43][44][45][46][47][48]: the solid line shows the theoretical prediction for superplastic flow in conventional metals not processed using SPD techniques.…”

Effect of Mn and Fe on the Formation of Fe- and Mn-Rich Intermetallics in Al–5Mg–Mn Alloys Solidified Under Near-Rapid Cooling

“…Extensive research had been carried out on the Al–Mg–Mn alloys, and a large number of investigations focused on microstructures and properties [ 12 , 13 , 14 ], superplasticity [ 15 , 16 , 17 ], ultrafine grain [ 18 , 19 , 20 , 21 , 22 ], and adding element [ 23 , 24 , 25 , 26 ], etc. Al–Mg–Mn aluminum alloy sheet materials produced using the CC process have also been widely investigated [ 27 , 28 , 29 , 30 , 31 ].…”

Microstructure and Mechanical Properties of Al-5Mg-0.8Mn Alloys with Various Contents of Fe and Si Cast under Near-Rapid Cooling

“…Extensive research to improve the AA5083 alloy had been conducted with emphasis on the microstructures and mechanical properties [8][9][10][11], superplasticity [12][13][14][15], ultrafine grain [16][17][18][19][20] and adding element [21][22][23][24], etc. Recently, research was carried out on the formation of the Fe-and Mn-rich intermetallics in the AA5083 type Al-Mg-Mn alloy [2].…”