The Quantitative Operational Space for Three-dimensional Atom Probes

摘要

The availability of high pulse repetition rate voltage pulse generators and femtosecond pulsed lasers coupled with high speed multi-hit position-sensitive detectors enable the three-dimensional atom probe to be operated under a variety of experimental conditions. In addition, these new instruments enable a much wider range of materials to be characterized. The capability to pulse at very high pulse rates significantly reduces the time between the pulses and may reduce preferential field evaporation on the standing voltage applied to the specimen and biased compositional determinations. The primary operating parameters that may be selected by the user include standing voltage, pulse voltage (or pulse fraction), specimen temperature, pulse repetition rate and evaporation/detection rate. Therefore, the operational space for quantitative analysis of a range of materials has been investigated with local electrode atom probe equipped with a high pulse repetition rate voltage pulse generator and a ultra-fast pulsed laser. This operating space has been explored with the following systems: a binary alloy composed of elements with dramatically different evaporations fields; a material with a single isotope and low fraction of a solute; a multi-element commercial alloy; and a highly resistive material. The materials chosen for this study included an Fe-3.25% Si alloy, an aluminum alloy, a nickel based superalloy, a zirconium-based alloy and a semiconductor.