Influence of temperature cycles on strength and microstructure of spray-deposited Si–Al CE9F alloy

Abstract

A B S T R A C T This paper investigates the effects of temperature cycles between −55°C and 125°C (the temperature range for intended space application) on the strength and microstructure of spray deposited Si-Al CE9F alloy. After 500 cycles, the strength is significantly improved of 9% (i.e., 26 MPa). Moreover the Weibull modulus also undergoes a significant increase. Microstructure characterizations by XRD, SEM, EBSD and DSC evidence recovery and recrystallization processes in the Al phase, and subgrain development at grain boundaries in the Si phase, leading to lower crystallite size. A Hall-Petch dependence of mean strength to average crystallite size in Si is proposed as strengthening mechanism.