Hot-Working Window Identified for Crack-Prone Al-20Sc Alloy

Hot working of Al-20Sc alloy was stable only within a narrow range of 550–600 °C and strain rates of 0.01–0.1 s⁻¹, according to an experimental study designed to characterize deformation and cracking in the aluminum–scandium material. The researchers identified cracks within Al3Sc phases and at interfaces between Al3Sc and the surrounding aluminum matrix. After weighing deformation stability against microstructural evolution, they selected 550 °C and 0.1 s⁻¹ as the optimal tested hot-working parameters for rolling-process design.

The investigation examined Al-20Sc, expressed in atomic percent, across temperatures from 450 to 600 °C and strain rates from 0.01 to 1 s⁻¹. It was a laboratory study of the alloy’s hot-deformation response, with the results intended to guide rolling of Al-Sc alloy targets used in micro-electromechanical systems. The material is prone to cracking during deformation, making the temperature and strain-rate limits directly relevant to process planning. Within the tested range, the alloy did not deform consistently: stable behavior was confined to the upper portion of the temperature interval and the lower portion of the strain-rate interval.

Microstructural observations connected the cracking pattern to specific regions of the alloy. Cracks initiated predominantly inside the Al3Sc phase and along Al/Al3Sc phase interfaces rather than being distributed uniformly through the material. The investigators also established a constitutive equation to characterize the alloy’s response during hot deformation. The supplied study summary does not report the equation’s numerical form or fitted parameters, so its use here is limited to the verified conclusion that the researchers developed a model for the measured hot-deformation behavior.

Two changes within the tested range reduced the alloy’s susceptibility to brittle cracking: increasing deformation temperature and reducing strain rate. The findings show that these variables are coupled to deformation stability, but they do not indicate that heating can be increased without limit. At excessively high temperatures, the Al3Sc phase coarsens. The optimum therefore reflects the study’s combined assessment of deformation stability and microstructure rather than the highest temperature or fastest rate that appeared within the broader experimental matrix.

The reported optimum of 550 °C and 0.1 s⁻¹ lies within the stable hot-working window. It is also the upper end of the strain-rate interval identified as stable, but the summary does not provide separate quantitative measures of fracture resistance, energy consumption, production efficiency or rollability at each condition. The result should therefore be understood as the best operating point selected under the study’s criteria and tested conditions, not as a universal recipe for every geometry, loading history or manufacturing process. The work provides a focused basis for rolling-process design while leaving broader validation outside the reported scope.

Subject of Research: Experimental hot-deformation and cracking study of Al-20Sc alloy

Article Title: Thermal deformation behavior of Al-20Sc (at.%) alloy during hot deformation at medium temperatures

Article References: Song, H., Du, X., Wang, C., Feng, X., Liu, M., Yang, J., Wu, X., Li, Q., Sun, B., & He, J. (2026). Thermal deformation behavior of Al-20Sc (at.%) alloy during hot deformation at medium temperatures. Journal of Materials Science, 61(41), 32196-32209. https://doi.org/10.1007/s10853-026-13699-4

Image Credits: AI Generated

DOI: 10.1007/s10853-026-13699-4

Keywords: Al-20Sc alloy, hot deformation, brittle cracking, Al3Sc phase, strain rate, deformation temperature, microstructure, constitutive equation, rolling process, scandium alloy, Thermal, deformation