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.
CeGlaFlex project: wafer-thin, unbreakable and flexible ceramic and glass
25.04.2017 | Fraunhofer-Institut für Lasertechnik ILT
Additive manufacturing, from macro to nano
11.04.2017 | Laser Zentrum Hannover e.V.
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
28.04.2017 | Event News
20.04.2017 | Event News
18.04.2017 | Event News
28.04.2017 | Medical Engineering
28.04.2017 | Earth Sciences
28.04.2017 | Life Sciences