Advances in Small Specimen Testing Methods for Characterizing Tensile, Creep, and Fracture Properties of Materials

Abstract

Tensile, impact, and creep properties of materials are evaluated using standard test methods following ISO, ASTM, and other international testing standards. These testing methods use large specimens and are material-intensive. Three innovative small specimen testing methods, namely impression creep (IC), small punch creep (SPC), and ball indentation (BI), are discussed that can be used to determine the mechanical properties of materials. IC is used to study the creep deformation behaviour of materials. SPC is used to evaluate creep deformation and fracture properties of materials. Tensile and hardness properties and fracture toughness can be evaluated using BI method. Unlike in conventional testing methods, all these small specimen testing methods involve complex stresses which are also heterogeneous. Therefore, there is a certain amount of empiricism while characterizing mechanical properties using these methods. However, being material non-intensive, these methods have applications and advantages over conventional methods namely in material development, material performance evaluation, and characterization of mechanical properties of weld joints. This paper presents a comprehensive review of the recent advances in IC, SPC, and BI testing techniques and discusses their relative advantages and limitations.