How are most turbine blades attached to the turbine disc?

Most turbine blades are attached to the turbine disc using a method known as fir tree roots. This design features a root structure that resembles a fir tree, which fits into corresponding slots in the turbine disc. This arrangement allows for a secure mechanical connection while enabling the blades to withstand the high stresses and temperatures characteristic of turbine operation. The fir tree root design allows for expansion and contraction of the blade without risking failure, ensuring that the blades remain securely attached during the engine's operation. This method also facilitates easier maintenance and replacement of the blades when necessary, as they can be removed and reattached without specialized welding or bonding processes. The effectiveness of this attachment method contributes significantly to the reliability and performance of gas turbine engines.