Estimating the mechanical properties of a service-exposed component in a quasinondestructive manner implies sampling as little material as possible from the component itself. Different subsized or miniature specimens to be employed in the various fields of mechanical testing are presented and discussed: 1. Cylindrical specimens with circumferential crack for fracture toughness testing in the brittle regime and miniature disk-shaped specimens for the upper-shelf ductile regime. 2. Miniature reconstructed specimens for residual creep strength evaluation by means of isostress temperature-accelerated tests. 3. Small-size specimens for low-cycle fatigue testing with enhanced cycle frequency.
Data significance and transferability to actual components, as well as accuracy of results, are discussed. Particular emphasis is devoted to usually favorable comparisons obtained with respect to larger, conventional specimens considered by ASTM test standards.