Engineering

Grinding

Metallurgy

Materials science

Chemical engineering

Grain boundary

Thermodynamics

Grain size

Physics

Nanotechnology

Thermal

Microstructure

Nanoscopic scale

Nickel

Thermal stability

Copper

Science

Smaller but more thermally stable Synthesizing metals with extremely small (nanoscale) grain sizes makes for much stronger materials. However, very small–grained materials start to coarsen at relatively low temperatures, wiping out their most desirable properties. Zhou et al. discovered a way to avoid this problem by mechanically grinding copper and nickel at liquid nitrogen temperatures. The processing method creates low-angle grain boundaries between the nanograins, which promotes thermal stability. Science , this issue p. 526

Enhanced thermal stability of nanograined metals below a critical grain size