Effects of Trace Rare Earth (TRE) additions on thermal, crystal structure, and radiation shielding properties of CuAlMn high-temperature S-M alloys: A closer look at Cerium effect

Abstract

This study systematically investigates the effect of Ce addition on the thermal, structural, and radiation shielding properties of CuAlMn-based high-temperature shape memory alloys (HTSMAs). Among the different compositions, Ce-III demonstrated the most balanced performance, exhibiting optimized phase transformation behavior, microstructural refinement, and enhanced gamma-ray attenuation. Differential Scanning Calorimetry (DSC) analysis revealed that Ce-III exhibited lower transformation temperatures, with austenite start (A_s) and finish (A_f) temperatures of 378.13 °C and 429.75 °C, respectively, and martensite start (M_s) and finish (M_f) temperatures of 402.52 °C and 341.91 °C, suggesting improved thermal stability. Microstructural analysis indicated significant grain refinement, attributed to Ce's dislocation pinning effect, which contributed to enhanced strength and radiation attenuation. X-ray diffraction (XRD) patterns confirmed the formation of Ce-rich intermetallic phases, such as Mn_1.15Cu_3.85Ce and Cu₈Ce₄, which increased density and photon interaction probability. The Ce-III alloy exhibited superior linear attenuation coefficients and reduced half-value layer, reinforcing its effectiveness as a radiation shielding material. It can be concluded that Ce-III represents an optimal composition with a synergistic combination of structural stability, phase transformation control, and enhanced radiation shielding capabilities, making it a promising candidate for nuclear and high-radiation applications.