为了解决金属合金增材制造中相变检测的材料损伤, 针对金属合金增材制造提出一种基于激光诱导等离子光谱学(LIBS)的实时相变监测方法。试验采集激光熔覆Ni-Al与Ni-Fe合金的连续激光激发光谱信号, 然后检测熔覆材料物相组成与成分, 最后使用飞秒激光烧蚀上述Ni-Al与Ni-Fe合金并采集对应的飞秒激光激发光谱信号。对于采集的光谱信号, 采用谱线强度比构建标定曲线分析其与物相组成的关系并针对两种合金分别建立了四条标定曲线。结果显示, 当物相组成随着Ni元素浓度增加而由γ＇-Ni3Al和β-NiAl相向β-NiAl和γ-Ni相转变时, 连续与飞秒激光谱线强度比随着成分改变的标定曲线线性趋势在80.57 at.% Ni时发生突变, 而当物相组成为Ni3Fe相且随着Ni元素浓度增加未改变时, 谱线强度比随着成分改变的标定曲线的线性趋势不发生改变。标定曲线的线性趋势的改变可以有效地预测物相组成的改变且连续与飞秒激光光谱标定曲线有着相同的变化趋势。

To solve the problems of material damage, the method of real time phase transformation prediction in metallic alloy additive manufacturing based on laser-induced breakdown plasma spectroscopy is proposed. The continuous laser induced spectral signals have been acquired during Ni-Al and Ni-Fe alloy laser cladding, then the phase composition and composition of the cladding material have been detected. Finally, the femtosecond laser induced spectral signals have been acquired during femtosecond laser ablating Ni-Al and Ni-Fe alloys. For the collected spectral signals, using line intensity ratio to build calibration curve analyze its relationship with phase composition, and establish four calibration curves for each of the two alloys. The results show that when the phase composition changes from γ＇-Ni3Al and β-NiAl to β-NiAl and γ-Ni phases as the concentration of Ni increases, the linear trend of the calibration curve of continuous and femtosecond laser line intensity ratio changes with composition, changes abruptly at 80.57 at.% Ni. When the phase composition is Ni3Fe phase and does not change with the increase of the Ni element concentration, the linear trend of the calibration curve of line intensity ratio changes with composition, does not change. The change of the linear trend of the calibration curve can effectively predict the change of the phase composition, the continuous and femtosecond laser spectral calibration curve has the same tendency.