Microstructural evolution, magnetocaloric effect, mechanical and thermal properties of hot-pressed LaFe11.6Si1.4/Ce2Co7 composites prepared using strip-cast master alloy flakes

• Published in: Journal of magnetism and magnetic materials Vol. 525; p. 167652
• Main Authors: Zhong, X.C., Dong, X.T., Peng, D.R., Wu, S.M., Liu, C.L., Huang, J.H., Zhang, H., Long, K.W., Jiao, D.L., Qiu, W.Q., Yu, H.Y., Liu, Z.W., Ramanujan, R.V.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-05-2021
• Subjects: Heat treatment; Hot pressing; LaFe13-xSix based composites; Magnetocaloric effect; Mechanical property; Thermal conductivity; LaFe13-xSix based composites; Hot pressing; Thermal conductivity; Heat treatment; Magnetocaloric effect; Mechanical property
• ISSN: 0304-8853
• DOI: 10.1016/j.jmmm.2020.167652

•La(Fe,Si)13/Ce-Co composites were prepared by one-step sintering process.•At 1373K sintering, Ce2Co7 alloy can promote the peritectic reaction of 1:13 phase formation.•The diffusion of Ce/Co into the 1:13 majority phase improve the TC of these composites.•After sintering at 1373K/6h, high value of (σbc)max~450MPa and λ~7.5W/m∙K were obtained.•One-step sintering process can be used in production of high performance La(Fe,Si)13 based MCMs.
LaFe11.6Si1.4/Ce2Co7 composites were prepared using strip casting flakes (SC-flakes) and heat treated flakes (HT-flakes) by hot pressing, denoted as SC-HP and HT-HP, respectively. Subsequently, additional heat treatment was performed. The microstructure evolution, phase constitution, magnetocaloric and mechanical properties of these SC-HP and HT-HP samples over a large range of heat treatment temperatures and times were compared. Heat treatment at 1373 K for 12 h resulted in Ce and Co diffusion into La(Fe,Si)13 particles. An increase of Tpeak from 228 to 289 K and a large (–ΔSM)max increase from 1.89 to 5.01 J kg−1 K−1 (ΔH = 2 T) was observed in SC-HP samples. Combining hot pressing and heat treatment considerably reduces processing time. 90% of theoretical density, compressive strength greater than 450 MPa, large (–ΔSM)max of ~4.73–5.01 J kg−1 K−1 and good thermal conductivity (λ) above 5.5 Wm−1K−1 were also achieved, suggesting the practical use of such heat treated composites with attractive magnetocaloric, mechanical and thermal properties.