CAJ | 학술논문

分析了镍基合金740 H在不同状态下的组织结构和析出相的种类及其对室温硬度和冲击韧性的影响。供货态镍基合金740 H晶内含TiN和(Nb,Ti)C颗粒，晶界分布一些M23C6颗粒；经800℃×16 h标准热处理后，晶内析出细小γ'颗粒，晶界析出少量碳化物；硬度明显提高，冲击韧性显著降低，分别为304 HB和37.5 J/cm2。时效后，γ'相尺寸呈逐步增大趋势且与基体保持共格关系，晶界碳化物数量明显增多。750℃下时效300~3000 h 过程中硬度和韧性的变化范围分别为323~331 HB和25~35 J/cm2，时效态740 H韧性的稳定性高于740合金。
분석료얼기합금740 H재불동상태하적조직결구화석출상적충류급기대실온경도화충격인성적영향。공화태얼기합금740 H정내함TiN화(Nb,Ti)C과립，정계분포일사M23C6과립；경800℃×16 h표준열처리후，정내석출세소γ'과립，정계석출소량탄화물；경도명현제고，충격인성현저강저，분별위304 HB화37.5 J/cm2。시효후，γ'상척촌정축보증대추세차여기체보지공격관계，정계탄화물수량명현증다。750℃하시효300~3000 h 과정중경도화인성적변화범위분별위323~331 HB화25~35 J/cm2，시효태740 H인성적은정성고우740합금。
Microstructure and precipitates and their effects on the room-temperature hardness and impact toughness of alloy 740H with different conditions were investigated. The as-received alloy contains (Nb,Ti) C and TiN particles inside grains and some discontinuous M23C6 carbide particles along grain boundaries. After an aging treatment at 800℃ for 16h and cooled in air (standard heat-treated condition), a large number of extreme fineγ' particles precipitated within grains and small carbide particles are located along grain boundaries. The hardness is increased to 304HB and impact toughness is remarkably decreased to 37.5J/cm2 after standard heat treatment, respectively. At 750℃, aging results in an increase of M23C6 particles at grain boundaries and coarsening ofγ' phase. In the period of 300~3000h aging, the coherency betweenγ' and matrix is maintained and the hardness and toughness are 323~331HB and 25~35J/cm2, respectively. The stability of toughness of the aged alloy 740H is greater than those of the aged alloy 740.