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.
New technology for ultra-smooth polymer films
28.06.2018 | Fraunhofer-Institut für Organische Elektronik, Elektronenstrahl- und Plasmatechnik FEP
Diamond watch components
18.06.2018 | Schweizerischer Nationalfonds SNF
New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference
Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...
Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...
Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.
When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...
Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.
Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....
Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.
Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...
17.08.2018 | Event News
08.08.2018 | Event News
27.07.2018 | Event News
17.08.2018 | Physics and Astronomy
17.08.2018 | Information Technology
17.08.2018 | Life Sciences