7. Low-temperature properties

Thanks to their face-centered cubic crystal structure, aluminum and its alloys do not exhibit embrittlement at low temperatures, as is the case with face-centered cubic metals, which have a transition temperature below which they lose their toughness.

The mechanical strength of welded and unwelded aluminum alloys is higher at low temperatures than at room temperature. The difference, which is small up to – 80°C, becomes significant at lower temperatures. At – 196°C, the yield strengths and breaking loads of most aluminum alloys are, on average, 20% and 30% higher respectively than those measured at room temperature. These differences reach 35 and 50% at – 253°C, and are generally maintained or even increased at – 269°C, the temperature of liquid helium. The reader will find in the articles Numerical data on aluminum and aluminum alloys. Unalloyed aluminum...