硼和磷对铁镍基变形高温合金组织和持久性能的影响

Effect of Boron and Phosphorus on the Structure and Stress Rupture Properties

利用真空冶炼炉制备铁镍基变形高温合金,采用光学显微镜(OM)和扫描电子显微镜(SEM)观察标准热处理后B、P微合金化的微观组织。发现B和P对晶粒度的影响较小,B含量的增加可以显著增加MC碳化物的析出。当P含量在0.003%至0.005%时,B含量从0.016%降至0.005%,可以将合金在700℃/400MPa,700℃/425MPa下持久寿命提高至3.8倍。当B含量为0.005%,P含量从0.005%升至0.023%时,对持久性能影响较小。B、P的最佳控制量应在0.005%和0.023%附近。B、P在晶界处附近会产生竞争偏析,硼化物对于晶界有钉压作用,P可以阻碍位错运动,进而阻碍合金裂纹扩展。适量的B、P含量可以延长合金的持久寿命。

The Fe-Ni based superalloy is fabricated by induction furnace. The microstructure of boron and phosphorus after heat treatment was observed by optical microscope（ OM） and scanning electron microscope（ SEM）. Boron and phosphorus did not exhibit influence on the grain size. The increase of boron content can significantly increase the precipitation of MC carbide. When the phosphorus content increase from 0. 003 % to 0. 005 %,the boron content decreased from 0. 016 % to 0. 005 %,the stress rupture life of alloy was increased by 3. 8 times at 700 ℃ /400 MPa,700 ℃ /425 MPa. When the boron content is 0. 005 %,the phosphorus content increased from 0. 005 % to 0. 023 %,playing little effect on the stress rupture life. The proper content of boron and phosphorus should be controlled around 0. 005 % and 0. 023 %. Boron and phosphorus can compete segregation near the grain boundary. Boride has the role of press,phosphorus can hinder the movement of dislocations,which can hinder the crack growth of the alloy. Appropriate boron and phosphorus content of the alloy is useful for thestress rupture life.