Janaki Ram G D, Esplin C K, Stucker B E
Department of Mechanical and Aerospace Engineering, Utah State University, Logan, UT 84322-4130, USA.
J Mater Sci Mater Med. 2008 May;19(5):2105-11. doi: 10.1007/s10856-007-3078-6. Epub 2007 Nov 8.
There is a growing interest in metal-on-metal bearing surfaces for orthopedic implants. Although some success has been achieved in applications like hip implants which involve a large contact area, non-conforming joints, such as knees, have proved more difficult. The current work examines the applicability of a novel additive manufacturing process, Laser Engineered Net Shaping (LENS), the registered trademark and service mark of Sandia National Laboratories and Sandia Corporation), for producing CoCrMo implants. A series of experiments were conducted to determine the optimum parameters for deposition of CoCrMo. Microstructural studies, hardness tests, and dry sand/rubber wheel abrasive wear tests were conducted on the LENS deposits. The results showed that metallurgically sound deposits can be produced using the LENS process under optimized conditions. The hardness of the LENS deposited CoCrMo was found to be comparable to that of standard CoCrMo wrought material; however, wear tests indicated that LENS deposits were considerably less resistant to abrasive wear than wrought CoCrMo. The reasons for this behaviour are discussed based on microstructural observations.
人们对用于骨科植入物的金属对金属轴承表面的兴趣与日俱增。尽管在诸如髋关节植入物等涉及大接触面积的应用中已取得了一些成功，但事实证明，对于像膝关节这样的非匹配关节，情况更为棘手。当前的工作考察了一种新型增材制造工艺——激光工程化净成形（LENS，桑迪亚国家实验室和桑迪亚公司的注册商标及服务商标）用于生产钴铬钼合金植入物的适用性。进行了一系列实验以确定钴铬钼合金沉积的最佳参数。对激光工程化净成形沉积物进行了微观结构研究、硬度测试以及干砂/橡胶轮磨料磨损测试。结果表明，在优化条件下使用激光工程化净成形工艺能够生产出冶金质量良好的沉积物。发现激光工程化净成形沉积的钴铬钼合金的硬度与标准钴铬钼锻造材料相当；然而，磨损测试表明，激光工程化净成形沉积物的抗磨料磨损能力远低于锻造钴铬钼合金。基于微观结构观察对这种行为的原因进行了讨论。
