Fabrication of Fe-Mn-Si-Cr Shape Memory Alloy Fiber/Aluminum Matrix Smart Composite by Casting

Abstract

If the composites are reinforced by the shape memory alloy (SMA) ber that shrinks in the matrix, one can introduce an arti cial compressive residual stress along the direction of the shrinkage. In our previous study, an SMA ber/plaster smart composite, using Fe-Mn-Si-Cr alloy bers, was fabricated and it was found that the bending strength of the composite was improved by the compressive stress due to the shape recovery force of the SMA bers. However, the imperfect bonding at interface between SMA ber and plaster matrix decreased the bending strength of fabricated composite. In this study, Al matrix smart composites containing Fe-Mn-Si-Cr SMA bers are studied, since it is well known that Fe and its alloys react with Al. Straight Fe-28.2mass%Mn-6.03mass%Si-5.11mass%Cr SMA bers were arranged on the ber holder, they were immersed into a mold with molten Al. During this step, ferrous SMA reacted with Al at ber/matrix interface, results in the good bonding strength at interface. After solidi cation, ferrous SMA ber/Al matrix composite could be obtained. This composite was subjected to the rolling deformation to induce the martensitic transformation from γ austenite to ε martensite in SMA bers. Then the composite was heated to induce the reverse transformation from ε martensite to γ austenite. The ferrous SMA bers in the composite shrank during this reverse transformation, which could induce tensile stress in bers and compressive stress in the matrix. This compressive stress in the matrix is a key factor that enhances the mechanical properties of such smart composite. Mechanical properties of fabricated smart composites were also studied.

Iron-Based Shape Memory Alloys in Construction: Research, Applications and Opportunities

“…When Fe-SMA is employed as a measure of prestressing, the amount of prestress is the property of most concern to engineers. With the aim of increasing the shape recovery properties, many research groups across the world have been devoted to developing improved production and manufacturing processes, including but not limited to thermal mechanical training, adjusting the chemical compositions and heat treatment [ 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 ]. These efforts greatly enhance the reliability of Fe-SMA as an emerging prestressing strategy.…”