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316L不锈钢作为医用人工关节材料,具有价格低廉和综合性能优异的优点,但在生物医学应用方面的推广和应用受到现有制备工艺的制约。采用选区激光熔化技术制备316L多孔不锈钢,分析了其显微组织构成,并对扫描间距对其力学性能的影响开展了研究。研究结果表明,随着扫描间距的增大,相邻两个激光辐照区域的搭接率降低,316L多孔不锈钢的抗压强度及弹性模量均减小;由于激光热作用区的存在,半熔化的颗粒依附于预留孔壁内侧,导致最终实际孔径小于预留孔径。采用选区激光熔化技术制备的316L多孔不锈钢孔隙率为10.67%~30.26%,平均孔径尺寸在40~300μm之间,抗压强度为2 410~3 370MPa,弹性模量为6.0~10.8GPa。316L多孔不锈钢的组织主要为等轴晶并含有少量枝晶,等轴晶晶粒平均尺寸约为850nm,枝晶晶粒的宽度约为800nm。压缩断口形貌观察表明断口由均匀细小的圆形韧窝组成,表明其压缩破坏方式为韧性断裂。
As a medical prosthetic joint, 316L stainless steel has the advantages of low cost and excellent overall performance, but its application and promotion in biomedical applications are limited by the existing preparation processes. The 316L porous stainless steel was prepared by selective laser melting and its microstructure was analyzed. The influence of scanning pitch on its mechanical properties was also studied. The results show that with the increase of scanning distance, the lap-lap rate of the two adjacent laser irradiation regions decreases, and the compressive strength and elastic modulus of 316L porous stainless steel decrease. Due to the existence of laser thermal zone, The molten particles adhere to the inside of the reserved pore wall, resulting in a final actual pore size smaller than the reserved pore size. The porosity of 316L porous stainless steel prepared by the selective laser melting technology is 10.67% -30.26%, the average pore size is between 40-300μm, the compressive strength is 2-410-370MPa and the elastic modulus is 6.0-10.8GPa. The microstructure of 316L porous stainless steel is mainly equiaxed and contains a small amount of dendrites. The average size of equiaxed grains is about 850 nm, and the width of dendrite grains is about 800 nm. Compressive fracture morphology observation shows that the fracture consists of uniformly small circular dimples, indicating that the compression failure mode is ductile fracture.