Revealing the Thermal Damage Mechanism of an Al–Zr–Er Alloy Wire by Quantitative Calculation: The Contribution of Dislocations and Nano‐Precipitates

Abstract

The thermal damage mechanism of Al wires for long‐distance overhead transmission under extreme service conditions is an important scientific issue that restricts the design and development of high‐performance Al wires. In this study, the thermal damage mechanism of the Al–Zr–Er alloy wires with a good combination of ultimate tensile strength in 170.0 MPa and electrical conductivity in 61.42% IACS is investigated via a simulated high‐temperature service experiment. In the results, it is shown that strength evolution exhibits a negative exponential pattern mainly attributed to the partial dislocation recovery in the cold‐drawn Al wires based on the quantitative calculation. However, the nanoscale Al3(Zr, Er) precipitates exhibit good thermal stability. The strength residual rate of the Al–Zr–Er alloy wires exceeds 90% after the simulated high‐temperature treatment at 280 °C, which can be attributed to the strongly pinning effect of nanoscale Al3(Zr, Er) precipitates on the dislocations and the grain boundaries, finally leading to the larger Zener drag force as compared with the driving force for recrystallization, thereby achieving good heat resistance of Al–Zr–Er alloy wires.