Skip to main content Accessibility help

Precipitation Phenomena and Strain Hardening of Intermetallic Titanium Aluminides

  • J. Müllauer (a1) and F. Appel (a1)


In two-phase titanium aluminide alloys, the implementation of precipitation reactions is a widely utilized concept to control the microstructure and strengthen the material. A study has been made on the influence of carbide and boride precipitates on dislocation mobility and strengthening at 300 K. Compression tests were carried out for characterizing the mechanisms determining flow stress and dislocation glide resistance. The interaction mechanisms between the precipitates and dislocations were assessed by thermodynamic glide parameters and transmission electron microscopy. It has been shown that small titanium boride precipitates and carbide precipitates of perovskite type act as long-range dislocation glide obstacles. The interaction between the dislocations and the borides and carbides mainly leads to an athermal stress contribution. However, the dislocation-particle interactions are quite different. Small groups of borides are encircled by dislocations. This gives rise to the formation of loop structures the density of which increases with strain. On the contrary, the carbide precipitates are shearable and can be overcome without Orowan looping. This different behaviour is also reflected in the work hardening characteristics. Whereas the work hardening coefficient of the boron doped material increases with increasing B-concentration, it is independent of concentration in the case of the carbon-doped material.



Hide All
[1] Kim, Y-W., JOM 41 (1991), 24.
[2] Appel, F. and Wagner, R., Mater. Sci. Eng. (1998), R22, 187.
[3] Appel, F., Brossmann, U., Christoph, U., Eggert, St., Janschek, P., Lorenz, U., Müllauer, J., Oehring, M., and Paul, J.D.H., Adv. Eng. Mater. (2000), 2, No. 11, 699.
[4] Larsen, D. E., Mater. Res. Soc. Symp. Proc. (1990),Vol. 194, 285.
[5] Christoph, U., Appel, F., Wagner, R., Mater. Sci. Eng. A 239–240, (1997) 39.
[6] Appel, F., Sparka, U., Wagner, R., Intermetallics 7, (1999) 325.
[7] Tian, W. H. and Nemoto, M., in Gamma Titanium Aluminides, (eds. Kim, Y.-W., Wagner, R. and Yamaguchi, M.) TMS, Warrendale, PA, (1995), 689.

Precipitation Phenomena and Strain Hardening of Intermetallic Titanium Aluminides

  • J. Müllauer (a1) and F. Appel (a1)


Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed