Tensile testing machine for microscopic specimens

Abstract

The problems of the mechanical testing of whiskers and thin films having gauge lengths down to 0.2 mm and cross-sections as low as 8 x 10-7mm2 are discussed. A machine is described which gives load-strain curves for such specimens with minimum load increments of 0.5 mg f and with extension readings repeatable to 0.019 [mu]. A torsion balance applies and measures the load and the strain is obtained by a null method using a marker and a special optical arrangement in a projection microscope. A number of special design features are incorporated to ensure high stability.