Gauge Factor of Refractory High-Entropy Alloys

One of the most promising applications of high-entropy alloys (HEAs) is their use as materials for strain gauges. In order to study HEAs in the context of this application, it is necessary to be able to accurately and rapidly measure gauge factor (GF). This paper reports the results of testing and validation of a precision automated system for direct strain gauge testing of metal alloys. The technique has been applied in studies of both known strain-gauge alloys and new HEAs such as TiHfZrTa, TiHfNbTaZr, TiHfNbTa, and TiHfNbZr. It has been demonstrated that the HEAs under investigation display a markedly elevated GF with values ranging from 3.60 to 5.17. This is significantly higher than that observed in conventional materials employed in the fabrication of strain gauges, such as manganin, constantan, and nichrome. Furthermore, the examined HEAs demonstrate a considerable elastic limit, reaching up to 972 MPa. The analysis of the obtained data leads to the hypothesis that the anisotropy of the elastic properties of the material is an essential factor responsible for the high GF.