Effects of Zr/(Sc plus Zr) microalloying on dynamic recrystallization, dislocation density and hot workability of Al-Mg alloys during hot compression deformation

• The deformation behavior and microstructure characteristics of Al-6.00Mg, Al-6.00Mg-0.10Zr and Al-6.00Mg-0.25Sc-0.10Zr (wt.%) alloys were investigated by hot compression tests and electron microscopy methods. The results show that after deforming under the maximum processing efficiency condition (673 K, 0.01 s-1), dislocation densities of Al-6.00Mg, Al-6.00Mg-0.10Zr and Al-6.00Mg-0.25Sc-0.10Zr alloys are 2.68x1016, 8.93x1016 and 6.1x1017 m-2, respectively. Their dynamic recrystallization fractions are 19.8%, 15.0% and 12.7%, respectively. Kernel average misorientation (KAM) analyses indicate that dislocation accumulation near grain boundaries is enhanced by adding Zr or Sc+Zr. Besides, the established hot processing maps, based on the dynamic material model (DMM), reveal that the addition of Zr or Sc+Zr can reduce the range of low-temperature unstable domain but expand the unstable domain at high temperatures and high strains. The experimental results further verify that under the testing deformation condition, only the Al-6.00Mg-0.25Sc-0.10Zr alloy cracks at 773 K and 1 s-1.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Metallurgi och metalliska material (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Metallurgy and Metallic Materials (hsv//eng)

NATURVETENSKAP  -- Fysik -- Den kondenserade materiens fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Condensed Matter Physics (hsv//eng)

Nyckelord

Al−Mg alloys

Sc

Zr

hot deformation

dislocation density

dynamic recrystallization

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