X-ray computed tomography analysis of pore deformation in IN718 made with directed energy deposition
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Kafka, Orion L.↗
Engineering topics
Yu, Cheng
Publications and source records attributed to Yu, Cheng.
Image-based multiscale modeling with spatially varying microstructures from experiments: Demonstration with additively manufactured metal in fatigue and fracture
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Kafka, Orion L. (ORCID:0000000323338154)↗
Effect of a novel starch-based temperature rise inhibitor on cement hydration and microstructure development: The second peak study
Temperature rise inhibitor (TRI) modifies the exothermic process of cement hydration at early age and mitigates the buildup of cumulative heat, which sheds new light on solving the thermal cracking issue. After the main hydration peak, a broader “second peak” appears and brings the cumulative heat back to normal level within 7 days (for additions less than 0.15%). This study shows that the “second peak” can be attributed, almost exclusively, to C{sub 3}S hydration while triggered by C{sub 3}A hydration. In a pure C{sub 3}S system, the heat flow is depressed by TRI during the main hydration peak but never recovers after. In a monophase system composed of C{sub 3}S, C{sub 3}A and gypsum or a real cement paste, the ongoing precipitation of ettringite helps to pump out TRI polymer from the pore solution and eliminate the restriction on C-S-H nucleation. Afterwards, the precipitation of C-S-H accelerates again to form the “second peak”.
36 MATERIALS SCIENCE↗