Microstructure of particle-strengthened materials. A study on Ni-base superalloys and Al-Li base alloys

The theory of order hardening is used to calculate the contribution to the shear stress of a superlattice dislocation in a binary AL-Li alloy with 2.9 volume percent of small 6'(L1 21 Al 3 Li) precipitates (R = 7.2 nm). The measured increase of yield stress is in reasonable agreement with the calculated value. From the separation of a superlattice dislocation the APB energy of Al 3 Li is calculated to be 139 mJ/m2. Orowan looping occurs around larger 6' precipitates with radius 68 nm (4.5 volume percent). In commercial Al-Li base alloys the effect of Zr, Cu and Mg has been described and composite precipitates (Zr-rich core, 6' shell) are analyzed by EDS. ... Zie: Summary