Dr. Adrian Sabau
Computational Sciences and Engineering Division
Oak Ridge National Laboratory

Modeling of Hot-tearing and Microporosity Defects During Casting of Multicomponent Al-Cu Alloys in an Integrated Computational Materials Engineering Approach

ABSTRACT: Hot-tearing and microporosity are major casting defects that can have regular, well-rounded shapes, or irregular, interdendritic shapes. These defects are not a material property but rather a result of the combined effects of thermodynamic phenomena leading to phase precipitation at grain boundaries, solidification microstructure, interdendritic feeding, and stress evolution during solidification. The data on casting defects, including microstructure features, is crucial for evaluating the final performance-related properties of the cast components. Yet, the scarce availability of constitutive models for the simulation of hot-tearing and/or microporosity and the much longer computational times required for process simulations poses a challenge to the ICME models. However, to accelerate the introduction of new cast alloys, the modeling and simulation of multiphysical phenomena needs to be considered in the design and optimization of mechanical properties of cast components. In this presentation, the required models for the prediction of interdendritic casting defects, such as microporosity and hot tears, are reviewed. Numerical simulation results for microporosity formation are presented for A356, 356 and 319 aluminum alloys using ProCAST software. The calculated pressure drop of the interdendritic liquid was observed to be significant where high and interdendritic microporosity was observed. Hence, the regions of high-pressure drop can be used as an indicator on the severity of interdendritic microporosity defects. Experimental results for hot-tearing susceptibility are compared with those obtained from numerical simulations. The data for the measured load and displacement during casting were compared with those obtained from numerical simulations to assess the current state-of-the-art for hot-tearing modeling.

BIOGRAPHY: Dr. Adrian S. Sabau received an Engineer Diploma in Mechanical and Materials Processing from the University of Craiova, Romania and a PhD degree in Mechanical Engineering from Southern Methodist University in 1996. In 1999, Dr. Sabau joined Oak Ridge National Laboratory as a Research Staff Member of the Materials Science and Technology Division, where he worked as a Senior Research Staff Member from 2008. Since 2018, Dr. Sabau is a (senior) Computational Materials Scientist in the Computational Sciences & Engineering Division. Dr. Sabau is the recipient of three R&D 100 awards in process sciences. Dr. Sabau seeks to advance the materials processing, metal casting, photonic processing, and materials for energy applications through the development of computational and experimental methodologies for the property measurement, process analysis, and materials behavior in response to conditions experienced in service. Dr. Sabau published more than 160 technical papers.