Microstructure and properties controlling of Al-xGd alloys for thermal neutron absorbing

Abstract

A novel lightweight thermal neutron absorbing Al-xGd alloy (x = 2.5, 5, and 10 wt.%) with tunable mechanical properties was fabricated by induction melting followed by a rolling process and an annealing treatment. During solidification, the Al₃Gd phase predominantly formed and was distributed along grain boundaries. Cold rolling crushed and redistributed the Al₃Gd phase throughout the matrix. Furthermore, the large deformation imposed on the material during cold rolling enhanced the work hardening effect and promoted dynamic recrystallization. The load transfer strengthening effect was influenced by the size, volume fraction, and distribution of the second phase. The spheroidization of the second phase increased rapidly and then remained stable during 5000 h long-term aging at 400 °C. The thermal neutron absorbing performance of the Al-5Gd alloy is comparable to the 30 %B₄C/Al composite evaluated by Monte Carlo simulations. Furthermore, Al-5Gd alloy exhibited higher plasticity (>20 %). This novel Al-xGd alloy is a promising candidate for future lightweight thermal-neutron-absorbing materials.