Abdur Rahman Al Azad
Abdur Rahman Al Azad is a PhD researcher in the area of additive manufacturing (AM) process-structure-property modeling. He graduated from his bachelor’s in Mechanical Engineering with honours from Assam Engineering College, India and completed a master’s in Materials Science and Engineering at the Indian Institute of Technology Gandhinagar. His main research interests include metal AM, computational fluid dynamics and material characterisation.
Research Interests (Lay Summary)
Additive manufacturing (AM) is a layer by layer manufacturing process which has the capacity to manufacture metal parts with highly complex geometries that are difficult for conventional manufacturing methods. The layer-by-layer process involves a very complex thermal history that leads to porosity and anisotropy in the microstructure, which affects the quality of the final part. In order to produce tailored components with desired mechanical properties, basic knowledge about the mechanism of microstructure development and evolution during the AM process of metallic alloys is required.
Currently, the rapid development of computer technology and the need for a thorough understanding of the thermodynamics and kinetics of microstructure evolution have led to a need for microstructural simulation. Among the various methods such as finite element (FE), finite volume (FV), lattice Boltzmann (LB), cellular automata (CA), and phase field (PF)for microstructure evolution, Phase Field Models (PFM) are the most widely used.
A PFM describes a microstructure by using a set of conserved and non-conserved field variables that are continuous across the interfacial regions. The interface between two grains is defined as a narrow region (diffused interface) where the phase-field variables gradually vary between their values in the neighbouring grains. Due to its diffused nature, explicit tracking of the interface is avoided.
Abdur commenced his PhD in April 2019 and has been developing a computational model for the evolution of microstructure during 3D printing of metals, based on powder bed fusion processes. In particular, he is developing models of non-equilibrium alloy solidification, following local melting from a laser or electron beam. These models will enable simulation of columnar and equiaxed solidification, and the columnar-equiaxed transition in additive manufacturing processes. This evolving grain structure affects both defect formation and the final residual stresses and mechanical properties of the printed part.
The grain structure models will be based on Phase Field Methods. The significance of numerical modeling is to study the physical phenomena that take place during melting and subsequent solidification of Ti6Al4V powder, thus providing a better understanding of the SLM process mechanism. The results obtained from this work, along with experimental studies, will improve the quality of additively manufactured parts.