铁基激光成形板件显微组织与性能的研究

Microstructure and Properties of Fe-based Plate by Laser Cladding

通过侧轴同步送粉方式对不同Co含量的铁基粉末进行成形试验,得到尺寸为140mm×10mm×3mm的铁基激光成形薄板,并对其进行后续热处理。分析发现,激光成形薄板无裂纹、气孔,成形性良好,其组织由多层具有相同特点的结构组成,每层组织由相互平行且与基板垂直的枝晶及枝晶间化合物组成。Co可以起到固溶强化的作用,其含量为3%时,熔层的硬度(HRC)及剪切强度分别达到最大值37和461.0MPa。热处理后,枝晶中的固溶强化作用减弱,各试样的硬度及强度均下降。在1050℃淬火+600℃回火热处理后成形件组织得到细化,有新相析出。各试样的硬度及强度较300℃回火后均有所提高。

The 140 mm×10 mm×3 mm laser rapid prototyping Fe-based thin plate containing various Co contents were produced by the ways of off-axis powder feeding, and then the thin plate was treated by heat treatment. The results show that the absence of crack and gas-hole in the laser cladding Fe-based thin plate can be observed, showing acceptable formality. The structure of the thin plate is composed of multi-layer structure with the same features, in which every layer structure consists of parallel dendrite that is perpendicular to the base plate and the interdendritic compound. Hardness and shearing strength of the cladding can reach up to the maximum values of HV37 and 461 MPa, respectively, with 3% Co content as a result of Co promoting the growth of dendrite and the refinement of the interdendritic compound. However, hardness and shearing strength of the plates are decreased after heat treatment due to the decrease of the solution element content. Alternatively, the hardness and strength of the plates are higher than those of 300 ℃ temper, which is attributed to the refinement of structure and new phase precipitation from the structure in the plate after 1050 ℃ quenching plus 600 ℃ tempering.