分析了金属粉末激光选区烧结成形过程致密化机制。选择不同的参数对Fe-C混合粉末进行了激光烧结成形实验, 根据烧结件微观结构分析了金属粉末的致密化机制, 根据致密度数据分析成形参数与致密度的关系建立了数学模型。结果表明, Fe-C混合粉末在低功率激光作用下部分粉末熔化形成液相, 在液相的参与下粉末通过重排、溶解沉淀导致致密化。成形参数对致密度的影响归结于烧结过程中产生的液相量, 激光功率的增加、扫描间隔的减小、扫描速度的降低和切片层厚的减少都会提高烧结件的致密度。

Densification mechanism of metal powder sintered with selective laser was studied. Different parameters were used in the laser sintering of Fe-C mixed powder experiments. The densification mechanism of metal powder was analyzed by observing the microstructure of sintered part. Based on experiment, the relationship between the densification rate and forming parameters was studied and its mathematical model was established. The results show that part of powder melts into liquid phase by low power laser and the densification is caused by powders rearrangement, dissolution and deposition participated in the liquid phase. The affect of laser process parameters on densification rate is decided by the amount of liquid phase produced during laser sintering. With the increase of laser power, the decrease of scanning interval, scanning speed and piece thickness, the densification is improved.