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研究了热等静压(HIP)温度对K438合金显微组织和高温力学性能的影响。结果表明,1170℃/150 MPa/4 h和1177℃/150 MPa/4 h热等静压能使K438合金显微疏松闭合。合金标准热处理(ST)后,枝晶杆由大、小两种尺寸的γ’相组成,其中较大的γ’相尺寸约为0.2μm;热等静压后,γ’相尺寸变大,接近0.5μm,未析出较小尺寸的γ’相;HIP+ST后,重新析出大、小两种尺寸的γ’相。力学性能测试结果表明,与标准热处理态相比,加入热等静压后,合金的815℃/420 MPa持久寿命相当,850℃/365 MPa持久寿命和800℃抗拉强度降低,而800℃拉伸伸长率和断面收缩率显著提高,其中,1170℃热等静压状态合金的800℃抗拉强度从902 MPa降到836 MPa,伸长率从6.8%提高到16.6%,提高了144.1%。
The effect of hot isostatic pressing (HIP) temperature on the microstructure and mechanical properties of K438 alloy was investigated. The results show that hot isostatic pressing at 1170 ℃ / 150 MPa / 4 h and 1177 ℃ / 150 MPa / 4 h can make the microstructure of K438 alloy slightly undissolved. After standard heat treatment (ST), the dendrite rod is composed of large and small γ ’phases, of which the larger γ’ phase size is about 0.2μm. After hot isostatic pressing, the γ ’phase size becomes larger, Close to 0.5μm, no smaller size γ ’phase is precipitated. After HIP + ST, large and small size γ’ phases are re-precipitated. The results of mechanical properties test show that after hot isostatic pressing, the life of 815 ℃ / 420 MPa is comparable to that of the standard heat treatment, the long life of 850 ℃ / 365 MPa and the tensile strength of 800 ℃ are decreased, while the tensile strength of 800 ℃ The tensile elongation at break and the reduction of area at fracture were significantly increased. The tensile strength at 800 ℃ of the hot isostatic pressing at 1170 ℃ decreased from 902 MPa to 836 MPa, the elongation increased from 6.8% to 16.6%, and the elongation increased by 144.1% .