Heat resistant alloy member, method for manufacturing the same, and method for repairing the same
View Patent ↗A heat resistant alloy member that maintains the creep strength and improves the fatigue characteristics is provided. The heat resistant alloy member according to the present invention includes a recrystallized structure layer including finer grains on the surface of the member than those inside of the member. The recrystallized structure layer is formed by forming a stirred layer by giving processing strain to the surface of the member using a friction stir processing, and applying recrystallization heat treatment to the stirred layer for recrystallization.
1. A method for manufacturing a heat resistant alloy member, the member being made of a Ni-based alloy and comprising a coarse grain layer,
the method comprising the steps of:
forming a stirred layer by giving processing strain to at least a part of the surface of the coarse grain layer using a friction stir processing, and
forming a recrystallized structure layer including finer grains than the coarse grain layer, by applying recrystallization heat treatment to the stirred layer for recrystallization, whereby:
the recrystallized structure layer is composed of grains having an average size of 1 μm or more and 100 μm or less, and
a thickness of the recrystallized structure layer is 1 mm or more and 5 mm or less.
2. The method for manufacturing the heat resistant alloy member according to claim 1 , wherein the stirred layer is provided at least on a portion of the surface of the coarse grain layer where fatigue damages are expected to be incurred.
3. The method for manufacturing the heat resistant alloy member according to claim 1 , wherein the coarse grain layer is composed of grains having an average size of 1 mm or more.
4. The method for manufacturing the heat resistant alloy member according to claim 3 , wherein the stirred layer is provided at least on a portion of the surface of the coarse grain layer where fatigue damages are expected to be incurred.
5. A method for repairing a heat resistant alloy member, the member being made of a Ni-based alloy and comprising a coarse grain layer,
the method comprising the steps of:
forming a stirred layer by giving processing strain using a friction stir processing to at least a portion of the surface of the member where cracks have occurred due to fatigue damage, and
forming a recrystallized structure layer including finer grains than the coarse grain layer, by applying recrystallization heat treatment to the stirred layer for recrystallization, whereby:
the recrystallized structure layer is composed of grains having an average size of 1 μm or more and 100 μm or less, and
a thickness of the recrystallized structure layer is 1 mm or more and 5 mm or less.