Sequence of phase evolution during mechanically induced self-propagating reaction synthesis of TiB and TiB2 via magnetically controlled ball milling of titanium and boron powders

• A two-step nucleation of TiB2 occurs during controlled ball milling.
• Before ignition, nucleation of off-stoichiometric TiB2-x particles occurs.
• Partial crystallization of amorphous boron evolved before ignition.
• After ignition, evolution of large grains of TiB2 occurs for Ti34B66.
• Nano spheroidal TiB2 and platelike TiB particles occurs for Ti50B50 after ignition.