Turbine blade tip

A turbine blade, comprising:

• a generally elongated blade having a leading edge, a trailing edge, a pressure side extending from the leading edge to the trailing edge, a suction side extending from the leading edge to the trailing edge and opposite to the pressure side, a tip at a first end, and a root coupled to the blade at an end generally opposite the first end for supporting the blade and for coupling the blade to a disc;
• a tip rail coupled to the tip at the first end, extending radially outward and configured such that an outer surface of the tip rail is generally aligned with an outer side surface of the turbine blade defining a cross-sectional profile of the turbine blade for a portion of the outer side surface of the turbine blade, wherein a leading edge region recess is formed proximate to the leading edge between an inner edge of the tip rail on the suction side and an inner edge of the tip rail on the pressure side and defined by an outer surface of the tip of the generally elongated blade, and a trailing edge region recess is formed proximate to the trailing edge between an outer surface of the tip rail and a tip edge at an intersection between the outer side surface and the outer surface of the tip such that at least a portion of the tip edge at the pressure side is exposed without the tip rail;
• wherein the tip rail includes a gap located adjacent to the suction side of the generally elongated blade to limit the formation of stress in the tip rail along the suction side;
• wherein the gap in the tip rail is positioned in a midchord region of the suction side between the leading and trailing edges;
• and
• wherein the tip rail is formed from at least one single crystal alloy oriented in a low modulus direction such that a gap exists at a location in the tip rail where the axis of orientation is positioned at a 45 degree angle to the outer surface of the suction side to reduce stress on the tip rail.

A component for a turbine blade, comprising:

• a tip rail configured to be coupled to a tip of a gas turbine airfoil;
• wherein the tip rail extends radially outward and is configured such that an outer surface of the tip rail is generally aligned with an outer side surface of the turbine blade defining a cross-sectional profile of the turbine blade for a portion of the outer side surface of the turbine blade, wherein a leading edge region recess is formed between an inner edge of the tip rail on a suction side of the airfoil and an inner edge of the tip rail on a pressure side of the airfoil, and a trailing edge region recess is formed proximate to a trailing edge between an outer surface of the tip rail and a tip edge at an intersection between the outer side surface and the outer surface of the tip of the airfoil such that at least a portion of the tip edge at the pressure side is exposed without the tip rail;
• wherein the tip rail includes a gap located adjacent to the suction side of the airfoil to limit the formation of stress in the tip rail along the suction side;
• wherein the gap in the tip rail is positioned in a midchord region of the suction side between the leading and trailing edges;
• and
• wherein the tip rail is formed from at least one single crystal alloy oriented in a low modulus direction such that a gap exists at a location in the tip rail where the axis of orientation is positioned at a 45 degree angle to the outer surface of the suction side to reduce stress on the tip rail.