EFFECT OF HEATING SHOCK ON THE MICROSTRUCTURE OF γ-TiAl BASE ALLOY

Microstructural changes of a near fully lamellarγ-TiAl base alloy after heating shock and ageing treatment have been investigated.After infrared heating treatment,the coarse and fully lamellar (FL) structure (lamellar cluster size 300μm,lamellar spacing 1.3μm) of as-castγ-TiAl base alloy became a substable structure with extreme fine lamellar spacing (140 nm) as well as flat lamellar boundaries which could be transformed to a stable,fine,fully lamellar microstructure (lamellar cluster size 40μm) after 1260℃,6 h ageing treatment.