Experimental study on the piezoresistive effect of Mn–Cu alloy under high temperature and pressure and its application

Large volume presses are used to simulate extreme environments within the Earth, enabling the investigation of the physical properties of subsurface materials. However, existing pressure calibration methods do not facilitate in situ observation of continuously varying chamber pressures. The Mn-Cu alloy, known for its piezoresistive properties, has not been extensively studied under ultra-high temperatures. This study investigates the piezoresistive effect of a Mn-Cu alloy wire across a temperature range of room temperature to 1000 °C and pressures up to 4.5 GPa. The results demonstrate that the Mn-Cu alloy wire can be a reliable manometer for in situ pressure monitoring in large volume presses, providing accurate absolute pressure measurements.