Welcome to ICME-Welding
The research activities in the Group for Integrated Computational Materials Engineering (ICME) for Welding led by Dr. Wei Zhang encompass:
- Additive manufacturing of metals (powder bed and blown-powder)
- Light-metal and dissimilar-metal joining for transportation (automotive, shipbuilding etc.)
- Creep-resistance steels and alloys for power generation
- Inertia and linear friction welding
- Modeling of welding and additive manufacturing processes and materials (Abaqus, Sysweld, Flow-3D, DEFORM, LS-Dyna, and Thermo-Calc)
Dr. Zhang's google scholar page is here. For additional information, please contact him at " ".
U+RSW, a novel method for dissimilar metal joining
In their recent paper published in Materials & Design, Prof. Zhang and his colleagues described the development of a new ultrasonic plus resistance spot welding method for dissimilar metal joining. U+RSW was used to join 1-mm-thick AA6061-T6 to 0.9-mm-thick AISI 1008 steel with 0.4-mm-thick AA6061-T6 as the insert. At welding current of 16.5 kA, a less than 1.5-µm-thick layer of intermetallics was formed at the Al insert/steel interface, corresponding to a high joint strength of 3.2 kN and a nugget pull-out failure mode. The formation of such a thin layer of intermetallics is attributed to the metallurgical bond formed at Al to steel interface by USW, which in turn reduces the electrical resistance and temperature at this interface during subsequent RSW.
Structural support in additive manufacturing
For additive manufacturing of complex geometries, “sacrificial” structures, generally referred to as supports, are commonly deposited between the main part and the substrate to anchor overhanging features and prevent distortion induced by thermal-stress. In their recent paper published in the journal Additive Manufacturing, Prof. Zhang and his colleagues discussed the effect of such structural support on microstructure of additively manufacturing Nickel Alloy 718. Analytical equations, taking into account various laser processing parameters, material properties and support geometries, were developed to calculate the heat build-up and cooling conditions during laser-powder bed fusion.
Micro-resistance spot welding of dissimilar platinum to niobium wires
Thermo-electro-mechanical simulation was used to model the temperature and deformation behaviors during micro-resistance spot welding of dissimilar platinum to niobium wires. The results are published in a recent paper, Optimization of A Dissimilar Platinum to Niobium Micro-Resistance Weld: A Structure-Processing-Property Study, in Journal of Materials Science.
Softening of heat-affected zone
Prof. Wei Zhang's group recently developed a 3D fully coupled electro-thermo-mechanical model for resistance spot welding of aluminium silicon coated hot-stamped boron steel. A non-isothermal Johnson-Mehl-Avrami-Kolmogorov (JMAK) equation is coupled with the process model to accurately predict local softening of subcritical heat-affected zone (SCHAZ). This model is essential for computer-aided engineering (CAE) based design of light-weight and impactresistant structures. Detailed description of their results can be found in their recent paper published in Materials & Design.
High-Temperature Mechanical Testing
High-temperature stress-strain curves are essential input to numerical simulation of manufacturing processes such as welding, additive manufacturing and forging. A group of researchers, comprising Mr. Alexey Kuprienko (MS student), Dr. Ying Lu, Dr. Daniel Tung (currently at Sandia National Laboratories) and Prof. Wei Zhang, all with Dept. of Materials Science and Engineering, recently developed a unique high-temperature testing procedure based on Gleeble® and digital image correlation (DIC). The animation below shows the local strain map generated using DIC during testing at 1373 K (1100 C or 2012 F). Some additional information can be found here.
Simulation of powder recoating dynamics
Powder packing structure is a critical parameter for powder bed based additive manufacturing. Prof. Zhang's group has been developing a dynamic model based on discrete element method (DEM). Detailed description of the model is available in their paper just published in The International Journal of Advanced Manufacturing Technology. Integration of the powder model into the molten pool simulation was presented in the 2015 SFF paper and the 2016 AM paper.
Brief bio of Dr. Wei Zhang
Dr. Zhang is a Professor at the Department of Materials Science and Engineering - Welding Engineering Program in The Ohio State University. He is also an affiliated faculty member of The Simulation Innovation and Modeling Center (SIMCenter). Prior to coming to OSU in January 2013, he worked as a Senior Researcher at the Oak Ridge National Laboratory (ORNL) from 2008-2012 and as an Engineer Team Leader at the Edison Welding Institute (EWI) from 2004-2008. He earned his Ph.D. in Materials Science and Engineering from the Pennsylvania State University in Spring 2004. His B.S. and M.S. in Materials Science and Engineering were both earned at the Huazhong University of Science and Technology in China.
About Welding Engineering
Welding Engineering is much more than "Arcs and Sparks!" It is a multi-disciplinary engineering field that involves materials science, metallurgy and mechanical engineering. Computational modeling is an essential science and math skill of welding engineers to develop new products, solve problems, and ensure that welded structures are safe and a benefit to society.