Cambridge University researchers use lasers to "heat and strike" 3D printed steel

According to the University of Cambridge, researchers have developed a new method for 3D printing metal, which can help reduce costs and more effectively utilize resources. This method, developed by a research team led by the University of Cambridge, allows structural modifications to be "programmed" into metal alloys during 3D printing - fine-tuning their performance without the need for thousands of years of "heating and tapping" processes.

The new 3D printing method combines the best quality of two worlds: 3D printing makes complex shapes possible, and traditional methods allow for the engineering design capabilities of metal structures and performance. The research results are published in the journal Nature Communications.

3D printing has broad prospects, but it still has not been widely used in industry, mainly due to high production costs, "said Dr. Matteo Seita of the Engineering Department at the University of Cambridge, who led the research. One of the main drivers of these costs is the amount of adjustment required for materials after production.

Since the Bronze Age, metal parts have been made through the process of heating and beating. This method uses a hammer to harden the material and soften it through fire, allowing manufacturers to shape the metal into the desired shape while endowing it with physical properties such as flexibility or strength.

The reason why heating and beating are so effective is because they change the internal structure of the material, which can control its performance, "Seita said. That's why it's still in use thousands of years later.

One of the main drawbacks of current 3D printing technology is the inability to control the internal structure in the same way, which is why so many post production changes are needed. We are trying to come up with some methods to restore some structural engineering capabilities without the need for heating and tapping, which in turn will help reduce costs, "Seita said. If you can control the metal properties you want, you can take advantage of the green aspect of 3D printing.

Seita has collaborated with colleagues from Singapore, Switzerland, Finland, and Australia to develop a new 3D printed metal "formula" that can highly control the internal structure of materials when they are melted by laser.

By controlling the way the material solidifies after melting and the heat generated during the process, researchers can program the characteristics of the final material. Usually, metals are designed to be sturdy and tough, so they can be safely used for structural applications. 3D printed metal is inherently sturdy, but it is usually also very brittle.

The strategy developed by researchers triggers controlled reconfiguration of microstructure by placing 3D printed metal components in a furnace at relatively low temperatures, thereby fully controlling strength and toughness. Their method uses traditional laser based 3D printing technology, but has made some minor adjustments to the process.

We found that lasers can be used as' micro hammers' to harden metals during the 3D printing process, "Seita said. However, using the same laser to melt the metal a second time will relax the structure of the metal, allowing for structural reconfiguration when the parts are placed in the furnace.

Their 3D printed steel has undergone theoretical design and experimental verification, made of alternating regions of sturdy and tough materials, making its performance comparable to that of steel made by heating and beating.

We believe that this method can help reduce the cost of metal 3D printing, thereby improving the sustainability of the metal manufacturing industry, "Seita said. In the near future, we hope to bypass the low-temperature treatment in the furnace and further reduce the steps required before using 3D printed parts in engineering applications.

The team includes researchers from Nanyang University of Technology, the Science and Technology Research Bureau, the Paul Scherrer Institute, the VTT Technology Research Center in Finland, and the Australian Nuclear Science and Technology Organization. Matteo Seita is a researcher at St. John's College, Cambridge University.

Source: Laser Network