By combining focused ion beam milling methods with microtesting techniques and finite element simulation we probe the strength of microscopic alumina phases that can be used as reinforcements in the production of metal matrix composite materials. We present results from tests conducted on alumina fibres and compare data thus obtained with known macroscopic fibre properties derived from tensile tests conducted on long sections of the virgin fibres. We then transpose these methods towards the microscopic testing of irregularly shaped alumina particles that have potential for the reinforcement of aluminium.