A novel method of net-form materials synthesis has been conceived and initial verification experiments have been successfully completed. The method uses streams of highly uniform droplets of molten metal which are deposited onto a substrate in a controlled environment such as a vacuum or higher pressures of selected gases. The droplet deposition rate is controlled such that rapid solidification occurs leading to a net-formed material with small grain size and high structural integrity. By using novel droplet stream generation techniques the droplets are directed onto the substrate with very small angular and speed dispersions thereby making possible the synthesis of small detailed parts. Since the droplets are the same size (typically 30-150 microns in diameter) and travel at the same speed, the absence of pre-solidification droplets in the final product leads to a more homogeneous, and thus higher quality part than is normally achieved with other related techniques. Since the solidification rate determines the structural integrity of the net-formed part, the droplet deposition rate, speeds, and sizes are parameters which will be varied in the study. The homogeneity and grain structure of the net-formed parts will be examined both optically and with the use of an electron microscope, and their mechanical characteristics will be studied by subjecting formed parts to tests in both compression and tension. The reduction of the proposal process to practice may allow the rapid fabrication of parts directly from computer-based descriptions. The resulting parts may also be produced with novel, high strength structure.
