选区激光熔化技术制备316L多孔不锈钢工艺及性能研究

Study on the Process and Properties of Biomedical 316L Porous Stainless Steel Prepared by Selective Laser Melting Technique

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 the medical artificial joint material,316L porous stainless steel possesses the advantages of cheap prices and excellent synthetic property,but its promotion and application in biomedical applications is constrained by the current preparation process.In this paper selective laser melting technology has been used to prepare 316L porous stainless steel,of which the fibrous tissue has been analyzed,and the effect of scan spacing on its mechanical properties has been researched.The results indicated that with the increase of the scan spacing,the overlapping rate of two adjacent laser irradiation zones reduced,in addition,the compressive strength and elastic modulus of 316L porous stainless steel decreased.What’s more,owing to the exist of the laser heat-affected zone,half-melted particles attached to the inside of the reserved hole wall,which made the final actual pore diameter less than the reserved one.The porosity of the 316L porous stainless steel prepared by selective laser melting technology was 10.67% to 30.26%,the average pore size was 40-300μm,and the compressive strength ,modulus of elasticity were 2 410-3 370 MPa and 6.0-10.8 GPa respectively.The tissue of 316L Porous stainless steel consists of mainly of equiaxed（the grain size was 850 nm on average）and a small amount of dendrite（the width of the grain size was 1 μm）.According to the observation of compression fracture,it is indicated that the fracture was composed of uniform and fine circular dimple,caused by the ductile fracture.