Strengthening in Mg–Li matrix composites

• Published in: Composites science and technology Vol. 67; no. 9; pp. 1965 - 1973
• Main Authors: Trojanová, Z., Drozd, Z., Kúdela, S., Száraz, Z., Lukáč, P.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-07-2007; Elsevier
• Subjects: Applied sciences; Compression; Deformation; Exact sciences and technology; Fibre reinforced metals; Liquid metal infiltration; Mechanical properties; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metal matrix composites; Metals. Metallurgy; Powder metallurgy. Composite materials; Powder processing; Production techniques; Mechanical properties; Metal matrix composites; Powder processing; Compression; Deformation; Liquid metal infiltration; Grain size; Fibre reinforced metal; Temperature effect; Composite material; Dislocation density; Magnesium base alloys; Infiltration; Lithium alloy
• ISSN: 0266-3538; 1879-1050
• DOI: 10.1016/j.compscitech.2006.10.007

Mg–
xLi (
x
=
4,
8,
12) matrix composites reinforced with short
δ-alumina (Al
2O
3) fibres were manufactured by the pressure infiltration process. Mg–8Li composite reinforced by SiC was prepared by the powder metallurgical technology. With increasing lithium content, the Mg–Li matrix exhibits phase transitions from hcp, to hcp
+
bcc and to bcc phase. Compression tests of cylindrical composite samples were carried out at temperatures between 20 and 300
°C. The deformation behaviour of composites is significantly influenced by the structure of matrix and the preparation technique. The results obtained revealed that the flow stresses of the composites are substantially higher than those of unreinforced alloy. The reinforcing effect of fibres and particles decreases with increasing temperature. Different contributions to the strength of composites were evaluated. The shear stresses at fibre/matrix interface were of greatest importance in the fibres reinforced composites, while in the particles reinforced composites, the small grain size plays the crucial role. The contribution resulting from the increased dislocation density is also important.