Abstract The growth and microstructure properties of Ti (grade 2) joints brazed by a Zr 41.2 Ti 13.8 Ni 10.0 Cu 12.5 Be 22.5 bulk metallic glass alloy filler have been investigated with regard to the control through isothermal solidification. Two characteristic joints were prepared at different isothermal brazing conditions: an acicular growth structure including a continuous segregation in the central area (at 830 °C for 300 s), and a structure with coarse acicular grains throughout the joint (at 830 °C for 1800 s). The primary phase solidified isothermally was hexagonal α-Ti, and upon subsequent cooling, the secondary α- and γ-phases formed at the intercellular regions through a eutectoid decomposition of β-Ti. The γ-phase was identified as having a phase formula of [Ti,(Zr)] 2 (Cu,Ni) with a tetragonal Ti 2 Cu structure ( a = 2.955 A, c = 10.827 A, space group = I 4/mmm). This phase was grown on primary α-Ti grains with an orientation relationship of 10 1 ¯ 0 α ∥ (200) γ and 1 2 ¯ 1 3 ¯ α ∥ [031] γ . The isothermally-solidified, primary α-Ti grains dominating the entire joint were epitaxially grown, depending on the orientation of the randomly oriented Ti parent grains.