Development of Eutectic Based Self-healing in Al-Si Hypoeutectic Alloy
Mentor 1
Pradeep Rohatgi; Volkan Kilicli
Location
Union 340
Start Date
27-4-2018 12:00 PM
Description
Engineering materials have a limited practical life-span due to degradation over time, which can be caused by fatigue, wear, creep and environmental conditions. An ideal solution to this would be incorporating the self-repair function seen in biological processes into inorganic systems, or simply put, self-healing materials. While there are a number of self-healing methods, this study employed a hypoeutectic Al-Si aluminum alloy in tensile bar form. After forming microcracks throughout the material, the bars were heated above the eutectic melting temperature, so any cracks in the interdendritic region would be filled by the Al-Si mixture. The results of this experiment were gathered by placing the samples under tensile strain until fracture. Originally these trials, when compared to the fracture point of undamaged "virgin" samples, showed a strength retention of up to 45% and recovered 89% of total elongation, but by artificially aging the bars post-healing we were able to retain up to 75% of original strength. These results show a clear improvement to the productive life-span of the material, but they are representative of a healing system which has not fully reached its potential. Microstructure analysis showed some cracks unfilled. If the activation of the healing agent can be correctly distributed this could be applied to any number of issues. By employing self-healing materials in any industry such as aerospace, automotive, or even building materials, the life-span of critical structures can be increased, and maintenance can be greatly simplified. Just by applying the catalyst fracture and damage repair can be initiated.
Development of Eutectic Based Self-healing in Al-Si Hypoeutectic Alloy
Union 340
Engineering materials have a limited practical life-span due to degradation over time, which can be caused by fatigue, wear, creep and environmental conditions. An ideal solution to this would be incorporating the self-repair function seen in biological processes into inorganic systems, or simply put, self-healing materials. While there are a number of self-healing methods, this study employed a hypoeutectic Al-Si aluminum alloy in tensile bar form. After forming microcracks throughout the material, the bars were heated above the eutectic melting temperature, so any cracks in the interdendritic region would be filled by the Al-Si mixture. The results of this experiment were gathered by placing the samples under tensile strain until fracture. Originally these trials, when compared to the fracture point of undamaged "virgin" samples, showed a strength retention of up to 45% and recovered 89% of total elongation, but by artificially aging the bars post-healing we were able to retain up to 75% of original strength. These results show a clear improvement to the productive life-span of the material, but they are representative of a healing system which has not fully reached its potential. Microstructure analysis showed some cracks unfilled. If the activation of the healing agent can be correctly distributed this could be applied to any number of issues. By employing self-healing materials in any industry such as aerospace, automotive, or even building materials, the life-span of critical structures can be increased, and maintenance can be greatly simplified. Just by applying the catalyst fracture and damage repair can be initiated.
