A detonator for a hand grenade fuze comprises a detonator case; a slider that is transversely reciprocable in the detonator case from an unarmed position to an armed position, the slider including a longitudinal through-hole filled with a primary explosive; a spring that biases the slider to the unarmed position; an arming mechanism attached to the slider, the arming mechanism comprising a shape memory alloy; an explosive lead disposed below the slider; and a booster charge disposed below the explosive lead.