Ni-BASED DIRECTIONALLY SOLIDIFIED ALLOY

Abstract

The present invention provides first generation Ni-based directionally solidified alloy containing none of Co and Re, which has excellent TMF characteristics, creep property and environment-resistant characteristics, and is superior in cost performance in practical use. The Ni-based directionally solidified alloy according to one embodiment of the present invention consists of Cr: 6% by mass or more and 12% by mass or less; Mo: 0.4% by mass or more and 3.0% by mass or less; W: 6% by mass or more and 10% by mass or less; Al: 4.0% by mass or more and 6.5% by mass or less; Nb: 0% by mass or more and 1% by mass or less; Ta: 8% by mass or more and 12% by mass or less; Hf: 0% by mass or more and 0.15% by mass or less; Si: 0.01% by mass or more and 0.2% by mass or less; Zr: 0% by mass or more and 0.04% by mass or less; B: 0.01% by mass or more and 0.03% by mass or less; and C: 0.01% by mass or more and 0.3% by mass or less, and a balance of Ni and inevitable impurities.

1 . Ni-based directionally solidified alloy consisting of:
 Cr: 6% by mass or more and 12% by mass or less;   Mo: 0.4% by mass or more and 3.0% by mass or less;   W: 6% by mass or more and 10% by mass or less;   Al: 4.0% by mass or more and 6.5% by mass or less;   Nb: 0% by mass or more and 1% by mass or less;   Ta: 8% by mass or more and 12% by mass or less;   Hf: 0% by mass or more and 0.15% by mass or less;   Si: 0.01% by mass or more and 0.2% by mass or less;   Zr: 0% by mass or more and 0.04% by mass or less;   B: 0.01% by mass or more and 0.03% by mass or less; and   C: 0.01% by mass or more and 0.3% by mass or less, and   a balance of Ni and inevitable impurities.   
     
     
         2 . Ni-based directionally solidified alloy consisting of:
 Cr: 7% by mass or more and 12% by mass or less;   Mo: 0.4% by mass or more and 2.5% by mass or less;   W: 7% by mass or more and 10% by mass or less;   Al: 4.0% by mass or more and 6.5% by mass or less;   Nb: 0% by mass or more and 1% by mass or less;   Ta: 9% by mass or more and 11% by mass or less;   Hf: 0% by mass or more and 0.15% by mass or less;   Si: 0.01% by mass or more and 0.2% by mass or less;   Zr: 0% by mass or more and 0.04% by mass or less;   B: 0.01% by mass or more and 0.03% by mass or less; and   C: 0.01% by mass or more and 0.3% by mass or less, and   a balance of Ni and inevitable impurities.   
     
     
         3 . Ni-based directionally solidified alloy consisting of:
 Cr: 8% by mass or more and 10% by mass or less;   Mo: 0.4% by mass or more and 2.0% by mass or less;   W: 7% by mass or more and 9% by mass or less;   Al: 4.0% by mass or more and 6.5% by mass or less;   Nb: 0% by mass or more and 1% by mass or less;   Ta: 10% by mass or more and 11% by mass or less;   Hf: 0% by mass or more and 0.15% by mass or less;   Si: 0.01% by mass or more and 0.2% by mass or less;   Zr: 0% by mass or more and 0.04% by mass or less;   B: 0.01% by mass or more and 0.03% by mass or less; and   C: 0.01% by mass or more and 0.3% by mass or less, and   a balance of Ni and inevitable impurities.   
     
     
         4 . The Ni-based directionally solidified alloy according to  claim 1 , wherein
 a creep life at a temperature of 900° C. and stress of 392 MPa is 65 hours or more, and   a number of cycles in a thermo-mechanical fatigue (TMF) property test in predetermined operating conditions is 155 cycles or more.   
     
     
         5 . The Ni-based directionally solidified alloy according to  claim 1 , wherein
 a value of a Larson-Miller parameter at a temperature of 900° C. and stress of 392 MPa is 25.6 or more and 25.9 or less, and   a value of a Larson-Miller parameter at a temperature of 1100° C. and stress of 137 MPa is 28.8 or more and 29.3 or less.   
     
     
         6 . The Ni-based directionally solidified alloy according to  claim 5 , wherein a durable temperature is 960° C. or more and 1010° C. or less for a 1000-hour life, which is a creep life obtained from the value of the Larson-Miller parameter at the stress of 137 MPa. 
     
     
         7 . A sample made of the Ni-based directionally solidified alloy according to  claim 1 , wherein
 in a high temperature oxidation test for judging characteristics of the sample from: a change of a weight of the sample from just after being mirror-finished to after being subsequently heated at 1100° C. in an electric furnace in the atmosphere and held for 12 hours; and observation of a surface of the sample,   the change of the weight of the sample is −0.1 [mg/cm 2 ] or more and 0.3 [mg/cm 2 ] or less, and   the surface of the sample has metallic luster.   
     
     
         8 . The Ni-based directionally solidified alloy according to  claim 2 , wherein
 a creep life at a temperature of 900° C. and stress of 392 MPa is 65 hours or more, and   a number of cycles in a thermo-mechanical fatigue (TMF) property test in predetermined operating conditions is 155 cycles or more.   
     
     
         9 . The Ni-based directionally solidified alloy according to  claim 2 , wherein
 a value of a Larson-Miller parameter at a temperature of 900° C. and stress of 392 MPa is 25.6 or more and 25.9 or less, and   a value of a Larson-Miller parameter at a temperature of 1100° C. and stress of 137 MPa is 28.8 or more and 29.3 or less.   
     
     
         10 . The Ni-based directionally solidified alloy according to  claim 9 , wherein a durable temperature is 960° C. or more and 1010° C. or less for a 1000-hour life, which is a creep life obtained from the value of the Larson-Miller parameter at the stress of 137 MPa. 
     
     
         11 . A sample made of the Ni-based directionally solidified alloy according to  claim 2 , wherein
 in a high temperature oxidation test for judging characteristics of the sample from: a change of a weight of the sample from just after being mirror-finished to after being subsequently heated at 1100° C. in an electric furnace in the atmosphere and held for 12 hours; and observation of a surface of the sample,   the change of the weight of the sample is −0.1 [mg/cm2] or more and 0.3 [mg/cm2] or less, and   the surface of the sample has metallic luster.   
     
     
         12 . The Ni-based directionally solidified alloy according to  claim 3 , wherein
 a creep life at a temperature of 900° C. and stress of 392 MPa is 65 hours or more, and   a number of cycles in a thermo-mechanical fatigue (TMF) property test in predetermined operating conditions is 155 cycles or more.   
     
     
         13 . The Ni-based directionally solidified alloy according to  claim 3 , wherein
 a value of a Larson-Miller parameter at a temperature of 900° C. and stress of 392 MPa is 25.6 or more and 25.9 or less, and   a value of a Larson-Miller parameter at a temperature of 1100° C. and stress of 137 MPa is 28.8 or more and 29.3 or less.   
     
     
         14 . The Ni-based directionally solidified alloy according to  claim 13 , wherein a durable temperature is 960° C. or more and 1010° C. or less for a 1000-hour life, which is a creep life obtained from the value of the Larson-Miller parameter at the stress of 137 MPa. 
     
     
         15 . A sample made of the Ni-based directionally solidified alloy according to  claim 3 , wherein
 in a high temperature oxidation test for judging characteristics of the sample from: a change of a weight of the sample from just after being mirror-finished to after being subsequently heated at 1100° C. in an electric furnace in the atmosphere and held for 12 hours; and observation of a surface of the sample,   the change of the weight of the sample is −0.1 [mg/cm2] or more and 0.3 [mg/cm2] or less, and   the surface of the sample has metallic luster.