Element-by-element tracking of laser processing reveals how metallic alloys reorganize during microscale laser melting processes
High-power lasers that can selectively cut and join metallic products are becoming increasingly important in today’s manufacturing industry. Now, Yingchun Guan from the A*STAR Singapore Institute of Manufacturing Technology and her co-workers have developed a technique that reveals exactly how molten elements vaporize and move about inside a laser-generated surface ‘plume’1 — findings that can advance additive manufacturing techniques used to print three-dimensional (3D) objects.
Researchers investigating the feasibility of 3D-printed implant materials often turn to magnesium–aluminum (Mg–Al) alloys because they are lightweight, tough and biocompatible. Recently, the A*STAR team demonstrated that laser surface melting of these alloys enhances their corrosion resistance as a result of a notable enhancement in the surface concentration of aluminum. It is difficult, however, to make the link between the initial alloy composition and the final product after laser processing, as many complex interactions occur in the cloud-like plume of laser-generated vapor particles.
Guan and her team designed a new experimental setup that can quantify which molten alloy elements are ejected into the laser plume. They positioned a thin silicon substrate perpendicular to a Mg–Al-based alloy a few millimeters from the laser firing point. Laser pulses then generated a plume that deposited onto the silicon surface.
When the researchers used a scanning electron microscope (SEM) to examine the deposits, they saw clear evidence of a phase explosion — a mixture of liquid and vaporized particles thrown out by the laser impact. These liquid deposits rendered many sections of the silicon wafer unsuitable for quantitative analysis.
But by combining the element-identifying capability of the SEM with time-of-flight mass spectrometry, the team produced ‘mass-resolved images’ that reconstructed the distribution of gaseous secondary ions in the plume.
The mass-resolved images revealed that Mg ions were evenly dispersed at high concentrations inside the plume. In contrast, the population of Al ions rises in the middle of the near-field region close to the laser firing point. Analysis showed that the Al species in the plume ‘fly’ further than those of Mg because of their higher transport rates in the hot near-field region.
Guan notes that the site-specific analytical capabilities of this technique should give researchers finer control over selective surface vaporization of alloying elements for enhanced, high-tech applications. “Our chemical analysis of the transport rates and distribution of vaporized species in the plume offers improved understanding of critical laser processes, including those used in additive manufacturing,” she says.
Fraunhofer researchers develop measuring system for ZF factory in Saarbrücken
21.11.2017 | Fraunhofer-Institut für Zerstörungsfreie Prüfverfahren IZFP
New manufacturing process for SiC power devices opens market to more competition
14.09.2017 | North Carolina State University
Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...
Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.
To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...
The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.
Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...
With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong
Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...
An interdisciplinary group of researchers interfaced individual bacteria with a computer to build a hybrid bio-digital circuit - Study published in Nature Communications
Scientists at the Institute of Science and Technology Austria (IST Austria) have managed to control the behavior of individual bacteria by connecting them to a...
11.12.2017 | Event News
08.12.2017 | Event News
07.12.2017 | Event News
12.12.2017 | Earth Sciences
12.12.2017 | Power and Electrical Engineering
12.12.2017 | Life Sciences