Study on activation energy and strain rate sensitivity of closed-cell aluminium hybrid composite foam

• Published in: Journal of alloys and compounds Vol. 832; p. 154860
• Main Authors: Yadav, B.N., Muchhala, Dilip, Sriram, S., Mondal, D.P.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 15.08.2020; Elsevier BV
• Subjects: Activation energy; Aluminum base alloys; Carbon nano tube; Deformation; Dynamic recrystallization; Energy absorption; Foamed metals; High temperature; Hot deformation; Hybrid composites; Multi wall carbon nanotubes; Silicon carbide; Strain analysis; Strain rate sensitivity; Temperature effects; Hot deformation; Strain rate sensitivity; Activation energy; Carbon nano tube
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2020.154860

High-temperature deformation behavior of LM13 aluminium alloy foam and LM13-silicon carbide (SiC)-multiwall carbon nanotube (MWCNTs) hybrid composite foams (HCFs) was studied and compared with that of LM13-SiC and LM13-MWCNTs composite foams at a temperature range of 25 °C–400 °C and strain rate ranging from 0.001 to 1 s−1. It is noted that the plateau stress and energy absorption decreased with the increasing temperature but increased with increasing the strain rate. Irrespective of kind of foams the combined effect of temperature and strain rate were investigated and the activation energy was determined for each type of foams as a function of temperature and strain rate. The cell walls collapse and microstructural changes during hot deformation were also examined. The hybrid composite foam exhibited the highest plateau stress, modulus, and energy absorption, whereas the alloy foams are softer foam with the lowest plateau stress, modulus, and energy absorption. At temperature <200 °C the deformation is vacancy and dislocation diffusion-controlled whereas at temperature >200 °C the deformation is controlled by dynamic recovery and recrystallization. [Display omitted] •TEM, FESEM images and Raman spectroscopy (mapping) confirm the uniform distribution of MWCNTs and SiC particles in the matrix.•The strain rate sensitivity is almost negligible up to 200°C. But above 200°C, the materials are comparatively strain rate sensitive. Alloy and CF1 more strain rate sensitive compared to CF2 and HCF.•The activation energy decreases with rising in temperature whereas increases with the addition of reinforcement particulate.•Activation energy also influenced by strain rate and decreases with an increase in strain rate.•The deformation behavior of all compositions sample are of brittle nature at room temperature. But between 200 °C to 300 °C the deformation nature changes from brittle to ductile.