tailieunhanh - Concise Dictionary of Materials Science Part 10

Tham khảo tài liệu 'concise dictionary of materials science part 10', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | tilt grain boundary Grain boundary whose disorientation axis is parallel to the boundary plane. In terms of the grain boundary orientation there can be symmetric and asymmetric tilt boundaries. time-temperature-transformation TTT diagram Presentation in coordinates temperature-time of the kinetics of phase transformations by lines corresponding to the onset and to the completion of the transformations. If the transformation is athermal the corresponding lines are horizontal see Figure . TTT diagram is also referred to as isothermal transformation diagram. D ra D CL Ẹ 0 Log time FIGURE TTT diagram for eutectoid alloy steel scheme . tinting See staining. titanium martensite Product of the martensitic transformation p a or p a . The phases a and a are supersaturated solid solutions of alloying elements in a-Ti and differ in the crystal system a -martensite is hexagonal whereas a -martensite is orthorhombic. In addition a -martensite occurs at a greater concentration of p-stabilizers in p-phase. The Burger orientation relationship as well as the habit planes 334 p or 441 p is observed between p- and a -phases. Since titanium martensite is a substitutional solid solution its formation is not accompanied by such a drastic strengthening as in the case of steel martensite. Crystallites of titanium martensite are usually of a lath shape. transcrystalline Observed or evolving inside grains. Intracrystalline intragran-ular and transgranular are synonyms for transcrystalline. transcrystallization zone See columnar zone. transformation hysteresis Difference between the temperature of the start of a phase transition upon heating and that upon cooling see superheating and undercooling . It is also referred to as thermal hysteresis. transformation-induced plasticity TRIP Increase in both the ductility and strain hardening of austenitic steels caused by the formation of strain-induced martensite. An increase in ductility can be explained by the fact that martensitic .