Stabilizing nanoprecipitates in Al-Cu alloys for creep resistance at 300°C

By Yuan Gao, C. Yang, J. Y. Zhang, L. Cao, G. Liu, Sun Jinru, Evan Ma. Materials Research Letters, 2018

199 citations recorded by the source corpus.

ABSTRACT Commercial precipitation-hardened Al-Cu alloys are normally used at temperatures below its ageing temperature of ∼225°C, to avoid thermally induced precipitate coarsening and resultant softening. Making such popular Al alloys creep resistant at or above 300°C is thus challenging. Here we present a modified precipitation protocol, exploiting Sc-microalloying and a carefully designed three-step heat treatment to enhance Sc segregation at the matrix/θ′-Al2Cu precipitate interfaces. The stabilized nanoprecipitates enable an order-of-magnitude reduction in creep rate at 300°C, demonstrating the room for microstructure improvement and the potential for property elevation in traditional engineering alloys through innovative processing coupled with synergetic alloying elements. GRAPHICAL ABSTRACT IMPACT STATEMENT A carefully designed precipitation protocol produces stable nanoprecipitates in Sc-microalloyed Al-Cu alloys, rendering an order-of-magnitude elevation of creep resistance at 300°C.

Subfields: Aerospace Engineering, Materials Chemistry, Mechanical Engineering

View Paper: https://www.semanticscholar.org/paper/a6a241f9b6a6e3eb84086709006cdedb897e1ebe