Gas turbine engine rotation unit constituent member and method for producing same

A method for manufacturing a component that constitutes a rotor assembly of a gas turbine engine, the method comprising:

• constructing a rotor assembly component made from a metal;
• and
• forming a hard particle layer, the forming including irradiating of directed energy beam towards a surface of the rotor assembly component body and delivering only a powder of hard particles in the form of a jet stream onto an area thereof towards which the directed energy beam is irradiated, the hard particles being made from a material harder than a material forming the rotor assembly component body, the hard particle layer including a mass of the hard particles and a matrix material retaining the hard particles and made solely from the material forming the rotor assembly component body.