改型K21合金高温拉伸强度研究

Research on High-temperature Tensile Strength of Modified K21 Superalloy

对经真空熔炼浇注的改型K21合金分别在室温、800℃、900℃和950℃下进行拉伸试验。结果表明:改型K21合金的抗拉强度(σb)从室温的612.5MPa增大到800℃的805MPa,呈逐渐增大的趋势,800℃的抗拉强度具有较高值。900℃的瞬时抗拉强度下降为615MPa,与室温相当,950℃下降加速。伸长率从室温的7.0%降低为900℃的1.2%,呈逐渐降低的趋势,950℃时伸长率为2.2%,稍稍有所提高。因此,在低于900℃时,改型K21合金具有较好的强度,可作为900℃以下温度范围内的等温锻造用模具材料。

The microstructure evolution and tensile strength of modified K21 superalloy obtained by vacuum melting casting were investigated after tensile test at room temperature,800℃,900℃ and 950℃.The results show that the tensile strength of modified K21 superalloy is added from 612.5 MPa to 805 MPa as the temperature rising from room temperature to 800℃,which is the highest at 800℃. While it decreases above 800℃,the tensile strength is 612.5 MPa at 900℃,which is as the same as that of room temperature ,but it reduces quickly at 950℃.The elongation is reduced from 7.0% to 1.2% as the temperature rising from room temperature to 900℃.The elongation is 2.2% at 950℃, there is a little bit increase. Therefore, modified K21 superalloy ,which has a good strength below 900℃,can be used as a die materials of isothermal forging in this range of temperature.