固溶和时效处理对热轧态825合金微观组织的影响

Effect of solution and aging treatment on microstructure of hot rolled 825 alloy

利用光学显微镜、扫描电镜与透射电镜研究了固溶温度和时效处理对热轧态825合金晶粒尺寸和析出相的种类及其形态的影响。结果表明：1020~1250℃保温30 min固溶,合金的平均晶粒尺寸由45μm增大到330μm;1050~1080℃和1150~1200℃分别发生一次晶粒尺寸急剧长大的过程;计算出热轧态825合金的再结晶激活能约为279.14 k J/mol。经700℃×50 h时效与800℃×50 h、900℃×50 h时效,合金中晶界处的主要析出相分别为M23C6相和M6C相;700℃×50 h时效晶界上析出相呈网状、晶粒内部有大量弥散分布的Ti C颗粒;800℃×50 h时效晶界上的析出相呈链状,900℃×50 h时效过程中发生了再结晶。

The effects of solution temperature and aging treatment on grain size and types and morphology of precipitates of hot rolled 825 alloy were investigated by means of optical microscope, scanning electron microscopy and transmission electron microscopy. The results show that with the solution temperature increasing from 1020℃ to 1250℃ , the average grain size of the alloy solution treated for 30 rain increases from 45 μm to 330 μm; and the grain size increases rapidly at the solution temperature of 1050-1080 ℃ and 1150-1200℃. The recrystallization activation energy of the hot rolled 825 alloy is about 279.14 kJ/mol. After aging at 700℃ for 50 h, or aging at 800℃ for 50 h and at 900 ℃ for 50 h, the main precipitation phases at grain boundary of the 825 alloy are M23 C6 and M6 C phases, respectively. After aging at 700℃ for 50 h, the precipitation phase at the grain boundary shows a network distribution, and there are a large number of dispersed TiC particles in the grains. After aging at 800℃ for 50 h, the precipitates at the grain boundaries are in chains, and recrystallization of the 825 alloy occurs during aging at 900℃ for 50 h.