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本文测定了45钢试样从820℃淬火并经200℃、400℃、600℃和740℃保温1小时后炉冷的正电子寿命谱。实验在一般的快慢符合正电子谱仪上进行。~(22)Na放射源的强度约为20μCi,仪器分辨率300ps左右,总计数约3×10~5。寿命谱的数据处理在微型计算机上进行,程序在单高斯函数拟合分辨函数的基础上作了近似处理,所得结果如图1所示。由图1可见,对于淬火试样,τ_1和τ_2的数值比减接近,I_2>I_1。随着回火温度的增加,τ_1减少I_1增加,τ_2增加I_2减少,这与回火温度增加位错密度和点阵静畸变减少以及空位集中形成空位团相关。
In this paper, the furnace positron emission lifetime spectra of 45 steel samples quenched from 820 ℃ and annealed at 200 ℃, 400 ℃, 600 ℃ and 740 ℃ for 1 hour were measured. The experiment was performed on a normal electronic spectrometer in terms of average speed. The intensity of ~ (22) Na radioactive source is about 20μCi, the instrument resolution is about 300ps, and the total count is about 3 × 10 ~ 5. The life spectrum data processing is carried out on a microcomputer. The procedure is approximated on the basis of a single Gaussian function fitting resolution function, and the result is shown in FIG. 1. As can be seen from Figure 1, for the quenched specimens, the values of τ_1 and τ_2 decrease more closely, I_2> I_1. With the increase of tempering temperature, the decrease of τ_1, the increase of I_1 and the increase of τ_2, the decrease of I_2, which is related to the increase of the tempering temperature and the decrease of the static distortion of the lattice as well as the formation of vacancy clusters.