Grain Size, Precipitation Behavior, and Mechanical Properties through the Thickness of Al-Mg-Si Aluminum Alloy Rings Produced by Compact Cast-Rolling Compound Forming

摘要

Al-Mg-Si aluminum alloy rings were produced by compact cast-rolling compound forming (CRCF) with different initial rolling temperatures and feed rates. The grain size, precipitated particles and resultant mechanical properties through the thickness of the CRCF-produced aluminum alloy rings were studied. The grain sizes of the rings increased with increasing initial temperature. As the feed rate increased, fine grains with a homogeneous distribution were observed. Coarse grains with an inhomogeneous distribution near the center layer dominated compared to those near the surface layers. As the feed rate and temperature increased, the ultimate tensile strength and elongation were enhanced, due to the morphologies of precipitated particles transforming to granular and uniform distributions. The size of high-density nanosized second-phase particles increased with increasing temperature, and the intensity of the Mg2Si phase slightly increased. The presence of high-density dislocations implies that HRR deformation contributes to the formation of dislocations in the aluminum alloy rings. Due to the precipitation- and dislocation-strengthening effects, the high-density nanosized Mg2Si phase and dislocations contribute to the improvement in mechanical properties.

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