Material Science

This soldering iron has an evacuated copper capsule at the tip that contains a pellet of Bulk Metallic Glass (BMG) aboard the International Space Station (ISS). Prior to flight, researchers sealed a pellet of bulk metallic glass mixed with microscopic gas-generating particles into the copper ampoule under vacuum. Once heated in space, such as in this photograph, the particles generated gas and the BMG becomes a viscous liquid. The released gas made the sample foam within the capsule where each microscopic particle formed a gas-filled pore within the foam. The inset image shows the oxidation of the sample after several minutes of applying heat. Although hidden within the brass sleeve, the sample retained the foam shape when cooled, because the viscosity increased during cooling until it was solid.