Grain growth and grain size effects on the thermal expansion properties of an electrodeposited Fe-Ni invar alloy

The effects of grain growth and size on the thermal expansion behavior of an electrodeposited Fe-Ni invar alloy have been studied. The results showed a method of achieving different thermal expansion coefficients over a wide range of 3.1-7.8 × 10−6 K−1 for the same alloy through grain size control. The thermal expansion difference between grain boundaries and crystallites was enlarged in the invar alloy. The nanocrystalline samples exhibited moderate thermal stability up to 623 K and then abrupt grain growth, with a contraction in volume.