Washington State University researchers created a way to 3D-print two types of steel in the same circular layer using two welding machines. The bimetallic material is 33% to 42% stronger than either metal alone. The method uses common, inexpensive tools, so manufacturers and repair shops can use them rapidly. The study is published in the journal Nature Communications.
The method has vast applications, as any place that welds can use it. The researchers used welding equipment commonly found in automotive and machine shops, integrated inside a computer numerical control or CNC machine. The new hybrid setup creates parts using precise computer programming and two welding heads.
In a demo, two welding heads worked one right after the other on a circular layer to print two metals. It printed a corrosion-resistant, stainless-steel core inside an outer casing of mild steel. Since the metals shrink at different rates as they cool, internal pressure is created, clamping them together. Tests showed greater strength than either steel has on its own.
The capability to strengthen 3D-printed metal parts layer-by-layer could provide the ability to create strong, customized steel parts quickly. In the future, researchers see the potential for medical manufacturing processes that print joint replacements with durable titanium on the outside and an inner material such as magnetic steel with healing properties.