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为实现医用钴铬合金在口腔修复中的应用,利用选区激光熔化(SLM)技术,研究开发了激光选区熔化成型工艺并进行了弯曲、拉伸、硬度以及热处理实验。利用扫描电镜、粗糙度轮廓仪、硬度仪等检测手段,对激光选区成型的试件进行了显微组织、力学性能、粗糙度、腐蚀性能等测试分析。研究结果表明,激光选区熔化成型最佳工艺参数为激光功率200 W、扫描速度500mm/s、层厚25μm、扫描间距0.07mm及扫描策略为S型X、Y方向、层错;SLM原始试样抗拉强度为1 185MPa、硬度为431HV、延伸率为8.6%、断裂形式为准解理断裂,热处理后抗拉强度为1 375MPa、硬度为563HV、伸长率为3.1%;SLM原始试样自腐蚀电位为-717mV、自腐蚀电流密度为1.7×10~(-5) A/cm~2,热处理后自腐蚀电位为-10mV、自腐蚀电流密度为0.3×10~(-5) A/cm~2;SLM原始样粗糙度为13.793μm、表面重熔后粗糙度降为5.141μm,打磨后粗糙度降为2.24μm。因此,热处理能提高试样的强度和耐腐蚀性,但韧性有所降低。最后利用优化的工艺参数,选区激光熔化成型制备出高强度、低粗糙度和耐腐蚀的牙冠牙桥,并进行佩戴实验,基本符合义齿的性能要求。
In order to realize the application of medical cobalt-chromium alloy in dental restoration, the laser melting zone forming process was studied and the bending, stretching, hardness and heat treatment experiments were studied by using the selective laser melting (SLM) technique. The microstructure, mechanical properties, roughness and corrosion properties of the laser-selected specimens were analyzed by scanning electron microscopy, roughness profiler and hardness tester. The results show that the optimal laser melting process parameters are laser power of 200 W, scanning speed of 500 mm / s, layer thickness of 25 μm, scanning pitch of 0.07 mm and scanning strategy of S-type X, Y-direction and stacking fault. The tensile strength is 1 185MPa, the hardness is 431HV, the elongation is 8.6%, the fracture mode is quasi-cleavage fracture, the tensile strength is 1 375MPa after heat treatment, the hardness is 563HV and the elongation is 3.1% The corrosion potential is -717 mV, the self-corrosion current density is 1.7 × 10 -5 A / cm 2, the self-corrosion potential is -10 mV after heat treatment, and the self-corrosion current density is 0.3 × 10 -5 A / cm ~ 2; the original roughness of SLM is 13.793μm, the roughness after surface remelting is reduced to 5.141μm, and the roughness after grinding is reduced to 2.24μm. Therefore, the heat treatment can improve the strength and corrosion resistance of the sample, but the toughness is reduced. Finally, using the optimized process parameters, the laser welding of the selected area was used to prepare the crown bridge with high strength, low roughness and corrosion resistance. The wearing experiment was performed, which basically met the performance requirements of the denture.