Mechanical damage was investigated in polymethylmethacrylate toughened with core-shell (hard core) rubber particles. During a tensile experiment, volume changes, light absorption, light scattering and the small strain elastic modulus were recorded. Light scattering was quantitatively related to the number of damaged particles and a fast partial unloading technique allowed determination of the non elastic part of these changes in material properties. Experiments performed between 10~(-5) and 10~(-1) s~(-1) and between 20 and 70 °C showed time-temperature transitions. Three types of microstructural damage were observed: pure matrix plasticity at very low strain rates or high temperatures, rubber cavitation at correlated locations at medium strain rates and temperatures, and disordered cavitation, rubber tearing and matrix plasticity at high strain rates or low temperatures.
展开▼
