FRACTOGRAPHY AND ITS ROLE IN FRACTURE INTERPRETATION

Fundamental understanding of fracture requires accurate interpretation of fractography. Examples are drawn from recent work on titanium alum inide alloys based on both Ti3Al and TiAl. Although the fracture mode in these alloys is often characterized as ''cleavage,'' in reality the fracture surfaces are neither entirely cleavage-like, nor do the ''cl eavage'' regions generally correspond to the classical description of cleavage. Implications of such fractographic observations, and of mode l fracture calculations, are discussed. Needs for further work to clar ify fracture processes are also identified.