Fabrication of Metallic Nanocomponents by Forging of Ni3Al-Nanoparticles.

Abstract

ABSTRACTThe trend to manufacture components reduced in size at the micro- and nano-scale is obvious and is becoming more and more the state of art in designing actuators, sensors and chips. In recent years, nanoscale fabrication has developed considerably, but the fabrication of freestanding nanosize components is still a great challenge. The fabrication of metallic nanocomponents utilizing three basic steps is demonstrated here. First, metallic alloys are used as factories to produce a metallic raw stock of nano-objects/nanoparticles in large numbers. These objects are then isolated from the powder containing thousands of such objects inside a scanning electron microscope using manipulators, and placed on a micro-anvil or a die. Finally, the shape of the individual nano-object is changed by nanoforging using a microhammer to get specific geometries such as discs and more complex components such as gears and wheels in the near future. The almost cubic particles are essentially defect-free, therefore, provide very high strength (σ>2500MPa) in combination with excellent formability (|ϕ|>1,6). There are two approaches for forming these small particles. Upset forging is used to forge small discs (height<100nm) and to shape the nanoparticle in specific areas. Press forging into nano-dies is used to forge more complex structures. In this way free-standing, high-strength, metallic nanoobjects may be shaped into components with dimensions in the 100 nm range. By assembling such nano-components, high-performance microsystems can be fabricated, which are truly in the micrometre scale (the size ratio of a system to its component is typically 10:1).