基于响应面法优化激光选区熔化成型CoCrMo合金工艺及其电化学行为

Process optimization and electrochemical behavior of CoCrMo alloy fabricated by selective laser melting based on response surface method

为了快速直接制造结构复杂、性能优异的个性化医用金属植入体,保证成型件具有良好的组织结构和生物特性,通过激光选区熔化技术对满足ASTMF75要求的CoCrMo合金进行增材制造。通过正交试验和响应曲面设计方法优化致密度工艺参数,观察成型件的微观组织,分析试样在模拟人体体液环境中的耐腐蚀性,并探究热处理工艺对其耐腐蚀性的影响。结果表明:在激光功率168 W、扫描间距0.06 mm、扫描速度550 mm/s时,成型零件的致密度可以达到98.58%,且微观组织均匀。电化学实验结果显示试样的腐蚀电流密度值约为40μA/cm2,经过退火热处理后,腐蚀电流密度仅为20.86μA/cm2,其耐腐蚀性能优于铸造CoCrMo合金的,这为选区激光熔化成型CoCrMo合金在医学植入体方面的应用提供了依据。

In order to directly fabricate personalized medical metallic implants with complex structure and excellent properties and ensure the parts have good microstructure and biological characteristics, the CoCrMo alloy satisfying the requirement of ASTMF75 is fabricated by selective laser melting （SLM） technology. The parameters of relative density were optimized by orthogonal experiment and response surface design. The microstructure of the specimens was observed, and the corrosion characteristic of the samples in simulated body fluid environment was analyzed while the influence of heat treatment process on the corrosion resistance was explored. The results show when the laser power is 168 W, the scanning space is 0.06 mm and the scanning speed is 550 mm/s, the relative density of CoCrMo alloy samples fabricated by SLM can reach 98.58%, and the microstructure is homogeneous. The electrochemical experimental results demonstrate that the corrosion current density value of the sample is about 40μA/cm 2, and becomes only 20.86μA/cm2 after annealing heat treatment. The corrosion resistance is better than that of fabricated by casting methods, which provides the basis for the application of CoCrMo alloy directly fabricated by SLM in medical implants.