CAREER: Ultrasonically Assisted Wire Arc Additive Manufacturing of Metal Matrix Nanocomposites for High-strength, Lightweight Structures

点击翻译按钮获取中文摘要

This Faculty Early Career Development (CAREER) grant focuses on an innovative ultrasonically assisted wire arc additive manufacturing process for fabricating metal matrix nanocomposite structures in freeform and at large scale. Metal matrix nanocomposites are a promising class of lightweight materials with superior mechanical performance attributed to well-dispersed nanoparticles within the bulk. Wire arc additive manufacturing is based on arc welding principles in which a continuously fed metal wire is melted and deposited into a desired complex shape, layer-by-layer. The process enables the direct manufacture of metal matrix nanocomposite functional parts and is advantageous in distinctly high deposition rate and low cost compared with powder-based additive manufacturing processes. This project would facilitate wide applications of metal matrix nanocomposites for lightweight structures, which improves energy efficiency, reduces fuel consumption and benefits various transportation industries, thus contributing to national economy and security. Multidisciplinary and real-world problem-based student training at different levels are well integrated into this project. Research results are transformed into multiple outreach initiatives that increase manufacturing career awareness in young generations and under-represented minorities. The virtual lab tools promote distance and continuing education. All of these contribute to development of globally competitive and diverse STEM workforce. The goal of this research is to investigate ultrasonically assisted wire arc additive manufacturing of metal matrix nanocomposites. While lightweight, high strength components are possible in these materials, achieving superior mechanical properties is challenging due to agglomeration of nanoparticles in the repeated melting cycles, solidification defects, porosity and inferior as-cast microstructure. To improve wire arc additive manufacturing, this research utilizes superimposed ultrasonic vibration to disperse the nanoparticles, refine the microstructure and minimize the defects. Specific objectives are to (1) understand the interaction of acoustic and electromagnetic fields and nanoparticle dispersions on melt pool hydrodynamics, (2) reveal coupling principles of acoustic field and nanoparticles on microstructure evolution in the repeated melting and solidification cycles, and (3) integrate data-driven and physics-based approaches for high fidelity modeling and analysis. The ultrasonically assisted wire arc additive manufacturing system is equipped with multiple sensors for online thermal-mechanical-acoustic analysis for process monitoring and control. Parts built with this hybrid process under different conditions are subject to comprehensive evaluation and multi-scale microstructure characterization. To establish relationships between process parameters, deposition profile, microstructure and mechanical properties, emerging data science tools are utilized, which are regularized by physics-based molten pool, solidification and phase transformation models. This modeling framework enables computational and data efficient tools for analyzing complex nonlinear physics involved in various manufacturing processes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.