Researchers from Swiss Federal Laboratories for Materials Science and Technology (EMPA) have additively manufactured a partly magnetic metal structure. This is through the use of one kind of steel powder, by changing its attributes.
Represented as a tiny metallic chessboard, the item is made up of 16 squares. Eight of them are magnetic and the rest are non-magnetic. It is additively manufactured by the use of an LPBF, laser powder bed fusion method from one class of metal powder. The differing attributes were made just by altering the power and span of the laser. This is all while utilizing LPBF’s highest temperatures.
The capacity to make various alloy compositions with micrometer precision in one piece could potentially confirm helpful to the metal manufacturing and processing methodology.
“In 3D laser printing, we can easily reach temperatures of more than 2500 degrees Celsius locally,” says Christian Leinenbach, the leader of EMPA project.
He further says, “This allows us to vaporize various components of an alloy in a targeted manner – e.g. manganese, aluminum, zinc, carbon and many more – and thus locally change the chemical composition of the alloy.”
Metal LPBF additive manufacturing particularly, in specific Selective Laser Melting (SLM) or Direct Metal Laser Sintering (DMLS), has special benefits in forming strong pieces with compact geometries while decreasing the time and cost of the material.
But there are some notable drawbacks to the production method. In the LPBF procedure, the temperature of over 2,500 °C is attained in milliseconds. This triggers some pieces of the evaporation of metal material powder.
The EMPAexpers, Leinenbach and Aryan Arabi-Hashemi, came out to show how this clear disadvantage can be powered to help the production procedure. The research crew shows this by the use of special kind of stainless steel that was created around 20 years ago by the firm Hempel Special Metals in Dübendorf, and others.
The metal is called P2000 steel and does not have nickel, but has about 1% nitrogen. Furthermore, P2000 does not trigger allergies. It is suited well for medical usages as well. Sadly, at first sight it also appears irrelevant as a foundation material for LPBF additive manufacturing: in the melting region of the laser ray, the temperature swiftly peaks. This triggers the evaporation of a huge piece of the nitrogen in the metal. As a result, it forces the change of properties of the P2000 steel.
