Experimental investigation on impact of temperature on mechanical properties and microstructural damage of a bullet jacket material

Abstract During continuous firing, the bullet undergoes high-speed rotational motion within the gun barrel, causing intense friction between the bullet jacket and the inner barrel wall, which generates a large amount of heat. As the number of fired rounds increases, especially beyond 150 shots, the barrel temperature rises rapidly, and heat transfer through contact also leads to the heating of the bullet jacket. Therefore, studying the effect of temperature on jacket materials is of practical significance for understanding the interaction mechanism between the bullet and the gun barrel. This paper conducts high-temperature tensile tests on a specific bullet jacket material (H90 brass) to obtain yield strength, tensile strength, and elongation data at different temperatures, establishing an empirical mathematical model. Moreover, the Scanning Electron Microscope (SEM), which is commonly used to observe microstructures, is used to observe the fracture morphology and microstructure of tensile specimens. The test results indicate that as the temperature increases, the yield strength and tensile strength of the bullet jacket material decrease continuously, while the elongation after fracture initially decreases and then increases. Significant differences in fracture morphology and microstructure are seen when the temperature reaches 400 °C.