Heat Treatments for Stress Relieving AlSi9Cu3 Alloy Produced by Laser Powder Bed Fusion

Materials

卷:14

Ausonio Tuissi¹  Jacopo Fiocchi¹  Carlo Alberto Biffi¹  Alberto Fabrizi²  Giulio Timelli²  Chiara Colombo³  Laura Maria Vergani³ 

[1] CNR ICMATE, National Research Council, Institute of Condensed Matter Chemistry and Technologies for Energy, Unit of Lecco, CNR ICMATE, via Previati 1/e, 23900 Lecco, Italy;

[2] Department of Engineering and Management, University of Padua, Stradella San Nicola 3, 36100 Vicenza, Italy;

[3] Department of Mechanical Engineering, Politecnico di Milano, via La Masa 1, 20156 Milano, Italy;

关键词: laser powder bed fusion;    selective laser melting;    Al alloys;    AlSi9Cu3;    heat treatment;    microstructure;   

DOI  :  10.3390/ma14154184

来源: DOAJ

【 摘 要 】

The present work explores the effect of a stress relieving heat treatment on the microstructure, tensile properties and residual stresses of the laser powder bed fused AlSi9Cu3 alloy. In fact, the rapid cooling rates together with subsequent heating/cooling cycles occurred during layer by layer additive manufacturing production make low temperature heat treatments desirable for promoting stress relaxation as well as limited grain growth: this combination can offer the opportunity of obtaining the best compromise between high strength, good elongation to failure and limited residual stresses. The microstructural features were analysed, revealing that the high cooling rate, induced by the process, caused a large supersaturation of the aluminum matrix and the refinement of the eutectic structure. Microhardness versus time curve, performed at 250 °C, allowed to identify a stabilization of the mechanical property at a duration of 25 h. The microstructure and the mechanical properties of the samples heat treated at 25 h and at 64 h, considered as a reference for the conventionally produced alloy, were compared with the ones of the as-built alloy. Finally, it was shown that a 59% reduction of the principal residual stresses could be achieved after the 25 h-long treatment and such evolution was correlated to the mechanical behaviour.

【 授权许可】

Unknown