G99二次硬化钢的穆斯堡尔谱研究

Study of Secondary Hardening Steel G99 by Mssbauer Spectroscopy

用穆斯堡尔谱技术研究了高Ｃｏ－Ｎｉ二次硬化马氏体钢（Ｇ９９）在不同回火制度下的组织结构变化．实验结果表明，随着回火温度的升高，起初奥氏体量有所降低，在４８０℃回火５ｈ奥氏体量达到最低．随后，随着回火温度的升高，奥氏体量又较快地增加．碳化物含量也随回火温度变化而有所变化．值得注意的是马氏体中Ｃｏ和Ｎｉ替代铁原子而成为Ｆｅ－Ｃｏ和Ｆｅ－Ｎｉ近邻，也随回火温度变化而变化，在４８０℃处出现较高的峰值，且与屈服强度峰位一致．这说明Ｃｏ。

The change of microstructures in high Co Ni secondary hardening martensitic steel G99 with tempering temperature was studied by 57 Fe Mssbauer spectroscopy. The result show that the austenite constituent in the steel decreased with the increasing of tempering temperature at first, and it reached lowest at 480℃ for 5 h, then it increased with the increasing of tempering temperature. Carbides constituent also changed with temperature. It is important to note that the Fe Co or Fe Ni subspectrum resulted from the replacement of Fe atoms by Co or Ni atoms was different for different tempering temperatures. In its fractional area appeared a peak at 480℃, which agrees with yield strength. This shows that the distribution of Co and Ni is probably connected with yield strength.