材料期刊网

采用光纤激光器和同步送粉激光成型工艺技术,实验时通氩气进行真空保护,通过一定的激光工艺参数(激光功率1800W,扫描速度5 mm·s-1,送粉速度18 g·min-1,光斑直径3 mm)在45号钢基板上成功获得钴基高温合金块体样品.通过X射线衍射(XRD)、扫描电子显微镜(SEM)和能量分散谱(EDS)分析以及室温拉伸和耐磨实验研究钴基合金的激光成型件性能.结果表明钴基高温合金与基体之间形成良好的冶金结合,激光成型后的微观组织多为均匀细小的枝晶,由于存在重熔区,使得部分枝晶发生粗化现象,但无明显缺陷,主要由M6C,Cr23C6,CrCo金属间化合物和γ-Co基体相组成;成型件样品的拉伸断裂断口平整,无颈缩现象,属于脆性断裂,其断裂过程是韧窝-类解理的复合断裂;成型件样品磨损表面存在犁沟磨痕,磨损前后质量损失很小,耐磨性能优良,耐磨机制主要是磨粒磨损、黏着磨损、氧化磨损.

The laser experiment was carried out by vacuum protection,and blocks of cobalt base superalloy were successfully obtained on the 45 Steel matrixes by using fiber laser,synchronous powder feeding system and a certain laser parameters(laser power was 1800 W,scanning speed was 5 mm·s-1,powder feeding speed was 18 g·min-1 beam diameter was 3 mm).Laser forming properties of cobalt base superalloy were studied by means of scanning electronic microscopy (SEM),energy dispersive spectrometer (EDS),X-ray diffraction (XRD) techniques,room-temperature tensile test and wear resistance experiments.The results showed that good metallurgical bonding could be obtained between cobalt base superalloy and matrix;the most microstructure of laser forming part was uniform and fine dendrite,due to the presence of the heavy re-melting district,coarsening phenomenon occurred in dendrite,but there was no obvious defects;the laser-formed material mainly consisted of phases of M6 C,Cr23 C6,Cr-Co intermetallic and γ-Co matrix,tensile fracture of forming part sample was smooth,and there was no necking phenomenon,so the tensile fracture was brittle fracture,the fracture mechanism was mixed mode fracture of dimple and cleavage-like fracture;there was furrow wear scar on the worn surface of forming part sample,and mass loss was small before and after wear resistance experiments,so the formed block had a good wear-resistant property,the main wear mechanisms of formed block were abrasive wear,adhesive wear and oxidation wear.