A Miniaturized Mechanical Testing System for Small-Scale Specimen Testing

Abstract

In this paper a miniaturized mechanical testing system designed for multiple testing modes is described. The main testing modes include (1) constant displacement rate testing in uniaxial tensile, compressive, and cyclic loading; (2) load relaxation testing; and (3) indentation hardness testing with a controlled displacement rate or displacement (load relaxation) with an indentation probe size as small as a few micrometers in diameter. The system, originally developed for testing materials and interconnecting structures for microelectronic components, is designed so that tests in different modes can be performed with only minor modifications. For room temperature testing, the temperature stability of the system is better than 0.1°C. The maximum loading capacity and displacement range are ∼ 100 N and 5 cm, respectively, and the smallest displacements that can be controlled are ∼ 0.01 µm. The capabilities of the testing system in different testing modes are demonstrated. Tensile and load relaxation test results of thin wires (<0.1 mm in diameter) with an accuracy comparable to bulk specimen results are presented. Also reported are results from indentation load relaxation tests with indentation depths applicable to irradiated material testing. Correlations between the mechanical properties of miniaturized specimens and bulk properties are discussed.