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The aim of this study is to check the efficiency of boron in refining lamellar microstructures of TiAl alloys densified by Spark Plasma Sintering. Boron-containing TiAl₄₇Cr₂Nb₂B_0.6 and boron-free TiAl₄₇Cr₂Nb₂ alloys were consolidated at varying temperatures. Their microstructures were studied by both scanning and transmission electron microscopies and their tensile properties were measured at room temperature. The structures and chemical composition of borides were analyzed. With the formation of borides, this addition of boron reduces the final grain size and promotes the formation of an unusual quasi-lamellar microstructure during cooling. Borides act as obstacles to the growth of the α grains at high temperature. They are also nucleant of the γ lamellae during cooling, thus increasing the temperature of lamellar transformation. Due to this high temperature nucleation, the quasi-lamellar microstructure is …