High-strain-rate testing of beryllium copper at elevated temperatures

The flow stress of any given material in metal forming is sensitive to the working temperature and the rate of deformation. Research at high strain rates on tensile specimens at elevated temperatures was carried out in the 1940s by Manjoine and Nadai. Little work has been done on this topic since. At the University of Limerick in the early 1990s a machine was designed and manufactured, the purpose of which was the testing of materials at strain rates up to 700 s(-1) and temperatures of up to 800 degreesC. At that time tests were carried out on mild steel at strain rates of up to 300 s(-1) and at temperatures of 700 degreesC. The results obtained were in good agreement with the earlier work of Manjoine and Nadai. This paper describes the operation of the testing machine, which is used to test materials at high strain rates and at elevated temperatures. It also describes the interface between a PC and the testing rig, which consists of a data acquisition board and various other interface circuits. The paper also describes the method of carrying out high-strain-rate tests at elevated temperatures on beryllium copper. The results of these tests will also be discussed and conclusions drawn. (C) 2004 Elsevier B.V. All rights reserved.