When it comes to producing metal parts with very complex geometries, additive manufacturing (also known as 3D printing) beats conventional manufacturing methods hands down.
And additive manufacturing offers the potential to create metallic parts with desirable properties that can’t be achieved using traditional methods.
But there’s a hitch. Metal parts created with additive manufacturing have defects, such as pores and cracks in the material, that significantly compromise the finished part’s strength and durability.
“This is the key problem right now for metal additive manufacturing, and it means we can’t use these parts for critical applications where they need to bear loads without breaking,” says Lianyi Chen, who joined the UW-Madison mechanical engineering department in July 2019 as an assistant professor.
Chen is tackling this problem with his research, which involves studying the metal additive manufacturing process. By gaining a better understanding of the fundamental physics and dynamics at play within this complex process, Chen aims to design new processing technologies that enable manufacturers to 3D print consistent, highly reliable metal parts.
Solving the quality problem would be an important breakthrough in metal 3D printing, Chen says, and it would greatly expand the application areas for this technology.
“My goal is to take the metal processing to the next level, and also to make new metallic materials with much better performance,” he says. “Ultimately, this would allow us to 3D print high-quality metal parts that can be used for a long time without failing.”
Chen, who also is a fellow in the college’s Grainger Institute for Engineering, works on a prominent additive manufacturing technique called laser powder bed fusion. In this method, a laser moves repeatedly across layers of metallic powder, melting the material in select locations. The material then cools, forming the finished metal part.
His research is experimental with complimentary modeling, and he develops in-situ monitoring technology and advanced characterization techniques to study the whole manufacturing process across multiple length and time scales. This provides a window into what’s happening at a fundamental level in the manufacturing process and within the material itself. With these insights, Chen can tease out which parameters are important to control in the process to achieve the desired outcome.
“Fusion-based additive manufacturing gives us the opportunity to make the part at the same time we’re making the material, because we’re melting the material,” he says. “Integrating the material design with manufacturing, and being able to make changes to both at the same time, can give us a better chance of making a new material with improved properties.”
Chen earned his PhD in materials science, focusing on metallurgy, in 2009 from Zhejiang University in China. He then conducted postdoctoral research in manufacturing engineering in the UW-Madison mechanical engineering department from 2010 to 2013, and at UCLA from 2013 to 2014.
In his postdoctoral research, he worked on metal matrix nanocomposites. This research entailed integrating nanoscale particles or nanowires into a conventional metallic material, opening up new possibilities for designing better materials.
“By bringing nano-scale elements into the material, we can greatly enhance its performance, making it stronger, making it ductile or even making it resistant to radiation damage,” he says. “This is an important research area I will continue to pursue at UW-Madison. My long-term goal is to establish a new paradigm for metals design based on nano-scale elements.”
Prior to joining the UW-Madison faculty, he was an assistant professor at Missouri University of Science and Technology. He says UW-Madison’s research excellence, particularly in areas related to his work, was a big draw.
“This is a great university, and I’m excited by the many opportunities for collaboration here,” he says. “UW-Madison has very strong research in metallurgy and advanced manufacturing, as well as outstanding engineering faculty who do modeling and simulation that I’m interested in collaborating with.”
Chen has developed a new graduate-level course, called metal additive manufacturing, that he is excited to teach in spring 2020.
“The area of additive manufacturing is growing so fast, and this new course gives me the opportunity to bring all the latest, most advanced knowledge into the classroom,” he says.
Author: Adam Malecek