Turbine airfoil attachment with serration profile

A rotor blade comprising:

• a platform;
• an airfoil extending from the platform in a spanwise direction to a tip and in a chordwise direction from a leading edge to a trailing edge;
• and
• an attachment root extending from the platform opposite the airfoil, the attachment root comprising:
• a serration profile that is symmetric about a plane bisecting the serration profile;
• and
• a first lobe of the serration profile spaced from the plane and described relative to a line intersecting the serration profile that is normal to the plane, the first lobe comprising:
• a first contact surface defining a first acute angle between the first contact surface and the line, wherein the first acute angle equals forty-five degrees;
• and
• a first non-contact surface defining a second acute angle between the first non-contact surface and the line, wherein the second acute angle is greater than three degrees;
• and
• a second lobe of the serration profile spaced from the plane, the second lobe comprising:
• a second contact surface defining a third acute angle between the second contact surface and the line, wherein the third acute angle equals forty-five degrees;
• and
• a second non-contact surface defining a fourth acute angle between the second non-contact surface and the line, wherein the fourth acute angle is greater than the second acute angle.

A high-pressure turbine comprising:

• a rotor;
• an airfoil;
• an attachment root coupling the airfoil to the rotor, the attachment root comprising:
• a serration profile that is symmetric about a plane bisecting the serration profile;
• and
• a first lobe of the serration profile spaced from the plane and described relative to a line intersecting the serration profile that is normal to the plane, the first lobe comprising:
• a first contact surface defining a first acute angle between the first contact surface and the line, wherein the first acute angle equals forty-five degrees;
• and
• a first non-contact surface defining a second acute angle between the first non-contact surface and the line, wherein the second acute angle is greater than three degrees;
• and
• a second lobe of the serration profile spaced from the plane, the second lobe comprising:
• a second contact surface defining a third acute angle between the second contact surface and the line, wherein the third acute angle equals forty-five degrees;
• and
• a second non-contact surface defining a fourth acute angle between the second non-contact surface and the line, wherein the fourth acute angle is greater than the second acute angle.