(華中科技大學 材料成形與模具技術(shù)國家重點實驗室，武漢 430074)
摘 要: 采用激光選區(qū)熔化工藝(SLM)制備幾種不同成分的316L-nHA(納米羥基磷灰石nHA的體積分數(shù)分別為0、5%、10%、15%)復(fù)合材料，并測試其致密度與抗拉強度；利用SEM分析其組織及斷口形貌。結(jié)果表明，當nHA的含量為5%時，材料的致密度和抗拉強度與純不銹鋼的相近，掃描速度為350 mm/s時強度達到最大值634.6 MPa；當nHA含量增大至10%~15%時材料致密度和強度明顯降低，強度最高只有264.4 MPa。面能譜顯示nHA均勻分布在金屬基體中，呈彌散型金屬-HA微界面結(jié)合特征。nHA和316L熱膨脹系數(shù)的差異，且nHA中富含P，導致SLM過程中產(chǎn)生裂紋，當nHA含量由5%增大至15%時，裂紋密度明顯增大，且互相聯(lián)通。當nHA含量為5%時，提高掃描速度有利于抑制裂紋產(chǎn)生；當nHA含量增大至10%~15%時，由于P增多，增大掃描速度對裂紋的抑制作用較小。在適當?shù)牟牧吓浔群凸に嚄l件下利用SLM可制備出滿足承重骨修復(fù)體力學性能要求的316L-nHA復(fù)合材料，有望改善金屬植入體的生物相容性。
關(guān)鍵字: 納米羥基磷灰石；316L不銹鋼；生物復(fù)合材料；激光選區(qū)熔化；力學性能
（State Key Laboratory of Materials Processing and Die & Mould Technology,
Huazhong University of Science and Technology, Wuhan 430074, China）
Abstract:Different compositions of 316L-nHA biocomposites (volume fractions of nano hydroxyapatite (nHA) are 0, 5%, 10% and 15%, respectively) were prepared by selective laser melting (SLM) method. The density and tensile strength of the composites were tested. And their microstructures and fracture morphologies were observed using scanning electron microscopy (SEM). The results show that at the nHA content of 5%, the density and tensile strength of composite are close to those of the pure stainless steel, and the maximum tensile strength of 634.6 MPa is achieved at a scanning speed of 350 mm/s. The tensile strength and density of composites decrease significantly when the nHA content increases to 10%-15% and the maximum tensile strength is 264.4 MPa. The surface energy spectrum shows that HA uniformly distributes in the metal matrix and the micro interface of metal-HA composite presents diffusion characteristic. Due to the difference between nHA and 316L stainless steel in thermal expansion coefficient and abundant P in HA, the cracks develop during the SLM process. When the nHA content gradually increases from 5% to 15%, the crack density increases obviously and the cracks are interconnected. When the nHA content is 5%, increasing scanning speed is helpful to reduce the crack number. When the nHA content increases from 10% to 15%, the inhibitory effect on the crack of increasing scanning speed is smaller due to the increase of P content. Under the condition of appropriate ratio of material and process, using SLM method is able to prepare 316L-nHA biocomposite satisfying the mechanical properties requirement of load-bearing bone repairing, which is expected to improve the biocompatibility of the metallic implants.
Key words: nano hydroxyapatite; 316L stainless steel; bioactive composite; selective laser melting; mechanical property
