Structure analysis of graded AA2011–Al2O3/NaAlSi3O8 composites produced by thixoforming
Résumé
The work investigates a new processing route to produce graded composites AA2011/micro particles of corundum/albite (Al2O3/NaAlSi3O8), by means of semisolid forming. Different approaches were analysed to reduce reinforcing particles agglomeration, using Al powder and TiH2 as additives together with the reinforcement. Results show that the ceramic microparticles can be located in interglobular regions of the thixotropic material and within the globules. Location and distribution of ceramic particles depend on the spheroidisation mechanism of the alloy structure during heating to produce the thixotropic material; addition of Al powder promotes higher thickness of reinforced layer and more homogeneous distribution of the ceramic particles.