Superplastic behavior of an Al-bearing eutectoid steel

• Published in: Journal of materials science letters 2003-11, Vol.22 (22), p.1609-1611
• Main Authors: Barrales-Mora, L A, Hernandez-Silva, D, Sauce-Rangel, V, Araujo-Osorio, J E
• Format: Article
• Language: English
• ISSN: 0261-8028
• DOI: 10.1023/A:1026344726809

Superplasticity is the ability of some polycrystalline materials to achieve extremely large uniform elongations in tension, prior to failure. Most superplastic materials consist of two phases, where the main role of the second phase is stabilizing the grains against grain growth. Early attempts to develop superplasticity in plain carbon steels (carbon content lower than 1 %) were unsuccessful. This was attributed to the low carbide content (e.g., 12% in an eutectoid steel) necessary to prevent grain growth. The increase of the carbon content between 1.5% to 2.5% lead to the development of steels now designated as ultra high carbon steels (UHCS), which, properly processed, show superplastic behavior. A recent investigation showed, however, that superplastic elongations in steels depends not only on the carbide fraction but also on the carbide size and distribution. The effect of some alloying elements on the superplastic properties of UHCS has been investigated and reported in several papers. Best superplastic properties have been found in an UHCS-Al alloy, elongation higher than 1000% at high strain rates have been obtained in this kind of material. The beneficial effect of aluminum in UHCS has been demonstrated in steels with carbon contents higher than 1%, however, the effect of aluminum in steels with carbon content lower than 1 % has not been investigated extensively. In this work the effect of aluminum on the superplastic properties of an eutectoid steel (0.8% C) has been investigated.