High performance metals and alloys offer tremendous potential to improve energy efficiency and system performance for numerous applications. Nanotech Metallurgy (Nanotech Enabled Metals Manufacturing) is emerging to break the traditional barriers and to revolutionize the metals processing and manufacturing technologies. >>Read More
Bioresorbable Metallic Stents
Stents are small expandable tubes used to treat narrowed or weakened arteries in the body. In patients with coronary artery disease (CAD), stents are used to open narrowed arteries and help reducing symptoms such as chest pain (angina) or to help treat a heart attack. These types of stents are commonly called heart stents, but they are also referred to as cardiac or coronary stents. Heart stents are implanted in narrowed coronary arteries during a procedure called a percutaneous coronary intervention (PCI) or angioplasty. Stents help prevent the artery from becoming blocked again (restenosis).
Our research focuses on the material design and manufacturing of the bare metal stent, including Zn and Zn-Mg alloys, while using non-toxic and thermally stable nanoparticles to modify the strength, ductility, grain structure, corrosion rate and biodegradability. The novel bioresorbable stents have enabled a higher strength with high ductility, allowing smooth expansion of the metal mesh, as well as resist the artery contraction. Furthermore, they obtain small grain structure that could satisfy the bioresorbable stent requirement. Overall, the availability of the innovative biodegradable stent designed for the treatment of aortic and pulmonary artery obstructions would revolutionize the treatment of these diseases in pediatrics.
This research area focuses on bridging nanoscience and manufacturing toward scale-up nanomanufacturing of functional nanomaterials and systems for practical impacts. Our approach is to understand the fundamental manufacturing issues/barriers and then apply physics to create novel processing methods to achieve scale-up nanoproduction. >>Read More
Smart Manufacturing and Embedded Sensors
Embedded sensors will drive the frontiers of energy systems monitoring and diagnosis into a new level. We design and fabricate new thin-film high temperature thermocouples, heat flux sensors, and strain gauges, and synthesize them into various energy systems in a distributed manner for real-time measurement and monitoring of the actual temperature and strain data. >>Read More
Selective Laser Melting of metals/ceramics containing nanoparticles: Selective Laser Melting (SLM) is of significance to directly produce functional metallic/ceramic components with nanoparticles. The overarching goal of this study is to advance the fundamental understanding on the accumulative effects of nanoparticles on microstructure, material properties, surface finish/accuracy, and residual stress during SLM, and to considerably enhance the properties of the laser deposited parts, reduce surface and geometrical errors, and minimize residual stress by tuning the micro-/nano-structure, melt pool dynamics, and thermal gradient using nanoparticles.
Additive Manufacturing of “smart” metallic tooling: Functional tooling with distributed embedded sensor and actuator systems can be significant for both health monitoring and the effective control of static and transient phenomena during manufacturing processes. Our work pioneers the manufacturing of metallic structures with embedded micro electronic and optic sensors via Rapid Tooling, a process that uses Additive Manufacturing to directly fabricate tooling layer by layer. The potential applications of “smart” metal tooling structures are abundant for enhancing their functionality, serviceability, and life span. Thin film and optic sensors have been successfully embedded into layered metal structures through ultrasonic welding and diffusion bonding.
Meso/Micro Additive Manufacturing of Miniature Parts: Micro-/Meso manufacturing processes are bridging the gap between silicon-based MEMS processes and conventional miniature machining. The benefits of this fact include the ability to now fabricate micro/meso-scale parts (e.g. molds and dies) out of a greater range of materials and with more varied geometry than possible with lithography and etching. One of our research interests is to develop new SFF methodologies at the micro/meso-scale, especially for producing functional parts and mechanisms with micro-scale features.
Laser Micro/Nano Materials Processing and Manufacturing
Laser-material interactions, especially thermomechanical phenomena involved in laser micro/nano materials processing and manufacturing, are extremely complicated and depend both on the mechanical, thermal and optical properties of materials and on the laser’s parameters. It is of fundamental interest to investigate the transient thermomechanical phenomena near the interaction region. While numerous analytic and numerical models have been developed, little experimental results are available for a thorough understanding of transient thermomechanical phenomena during the laser based micro/nano processes. My past research focused on the fabrication and utilization of micro/nano thin-film sensors on various substrates for transient temperature measurement during laser micromachining and micropolishing. Transient temperatures have been successfully measured with superior temporal (in the order of ns) and spatial resolutions (about 150nm so far). The in-situ measured data can be used to improve existing analytical and numerical models.