[en] Alloys of Fe₇₇Ga₂₃B_x (x=0, 0.025, 0.050, 0.075 and 0.1) were heat treated at 1000 ^oC/10 h and characterized for microstructural features and magnetostriction. The study indicates that the parent alloy consists of three phases viz. A2 as the major phase and L1₂ and DO₃ as minor phases. However, the volume fraction of L1₂ and DO₃ decreases with B addition and as a result magnetostriction improves. The decrease in volume fraction of these phases is attributed to B-segregation to the grain boundary, which seems to prevent the formation of these phases. The alloy with x=0.1, however, exhibits an additional Fe₂B phase and consequently its presence leads to the re-emergence of the DO₃ phase, affecting the magnetostriction.