Microstructure evolutions of SiCp/AZ91 Mg matrix composites during hot compression

10 vol% 10 mu m SiCp/AZ91 composite fabricated by stir casting was compressed with four temperatures and four strain rates. Compression improved the SIC particle distribution of the composite. Particles segregation was easy to be reduced at higher compressive temperatures. Dynamic recrystallization (DRX) took place in the matrix during hot compression. DRX areas were mainly located near particle aggregations at grain boundaries. Temperatures and strain rates significantly affected the DRX behavior of the matrix, which causes the different microstructures of the composites compressed at different parameters. In addition, temperatures and strain rates also significantly affected the dislocations and twins of the matrix. The secondary twins were observed at higher strain rates. The twins recovered at the higher temperatures and lower strain rates. As temperatures increased, the density and morphology of the dislocations evidently changed. (C) 2012 Elsevier B.V. All rights reserved.