Rheological Behavior and the Formation of the Microstructure of a Composite Based on an Al-Zn-Mg-Cu Alloy with a 10% SiC Content

The paper deals with the rheological behavior and microstructure formation of a metal matrix composite (MMC) based on a matrix made of the V95 alloy (analogue of the 7075 alloy) with reinforcing SiC particles. The rheological behavior has been investigated from plastometric testing results on cylindrical specimen compression at temperatures ranging from 400 to 570 degrees C and strain rates ranging between 0.1 and 0.25 s(-1). It has been established that the flow stress curve for a V95/10% SiC MMC consists of a few pieces at 400 and 570 degrees C. First there is material hardening, then there is softening followed by another portion of hardening. At a temperature of 500 degrees C, instead of a descending branch, on the flow stress curve there is a steady horizontal portion followed by hardening. Electron backscatter diffraction has shown that dynamic recovery and dynamic recrystallization occur in a V95/10% SiC MMC under deformation. Dynamic recovery is more active at 500 degrees C and 570 degrees C than at 400 degrees C due to the annihilation of dislocations, and this is reflected in the formed microstructure.