激光粉末床熔融成形金刚石增强铝基复合材料  

Diamond reinforced aluminum matrix composites by laser powder bed fusion

作　　者：郜文哲 韩笑 魏海滨 路正朕 张利 李晓峰[1,3] GAO Wenzhe;HAN Xiao;WEI Haibin;LU Zhengzhen;ZHANG Li;LI Xiaofeng(School of Materials Science and Engineering,North University of China,Taiyuan 030051,China;School of Mechanical Engineering,North University of China,Taiyuan 030051,China;State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,China)

机构地区：[1]中北大学材料科学与工程学院,太原030051 [2]中北大学机械工程学院,太原030051 [3]中南大学粉末冶金国家重点实验室,长沙410083

出　　处：《粉末冶金技术》2024年第2期122-127,共6页Powder Metallurgy Technology

基　　金：国家自然科学基金资助项目(52375393,52071299);山西省科技创新人才团队资助项目(202304051001029);山西省科技成果转化引导专项资助项目(202204021301048);山西省重点研发计划资助项目(2210300058MZ,202202150401020)。

摘　　要：添加质量分数3%金刚石颗粒并利用激光粉末床熔融技术制备6061铝基复合材料。采用光学显微镜、扫描电子显微镜、X射线衍射仪、电子密度计、电子式万能试验机对3%金刚石/6061铝基复合材料的微观组织、相对密度和拉伸性能进行了表征与分析。结果表明:金刚石与Al基体反应生成了针状Al4C3相,并沉积在α-Al基体上,导致晶界位错密度增加,强度提高,抗失效能力增强。金刚石的添加促使6061铝基体中热裂纹消失,但存在孔洞缺陷。较低的扫描速度增加了激光光斑与被加工材料接触的时间,导致金刚石颗粒部分石墨化,铝基体部分蒸发,进而形成内部缺陷,降低了复合材料的相对密度(97%)。金刚石的加入显著提高了激光粉末床熔融技术成形金刚石/6061铝基复合材料的抗拉强度,当激光功率为350 W、扫描速度为800 mm·s-1时,复合材料的极限抗拉强度达到最大值244.2 MPa,屈服强度211.6 MPa,伸长率2.1%。6061 aluminum matrix composites added by 3%diamond particles(mass fraction)were prepared by laser powder bed fusion(LPBF).The microstructure,relative density,and tensile properties of the 3%diamond/6061 aluminum matrix composites were characterized and analyzed by optical microscope,scanning electron microscope,X-ray diffractometer,electronic densitometer,and electronic universal testing machine.Results show that the diamond reacts with the Al matrix,generating the needle-like Al4C3 phase,which deposits in theα-Al matrix.Those formed Al4C3 increases dislocations at the grain boundaries,enhances the materials’strength,and delays the failure to fracture.The addition of diamond facilitates the elimination of thermal cracks,but the porous defects remain in 6061 aluminum alloys.The lower scanning speed extends the contact duration between the laser spot and the processed material,leading to the graphitization of the added diamond and the partial evaporation of the Al matrix.Thus,the internal defects exist,exhibiting the low densification of the composite(relative density 97%).The addition of diamond significantly increases the tensile strength of the LPBF formed diamond/6061 aluminum matrix composites,and the ultimate tensile strength reaches the maximum value of 244.2 MPa,the yield strength is 211.6 MPa,and the elongation is 2.1%,respectively,when the laser power is 350 W and the scanning speed is 800 mm·s-1.

关 键 词：激光粉末床熔融 金刚石颗粒 铝基复合材料 工艺优化 力学性能 

分 类 号：TF124[冶金工程—粉末冶金] TG146.2[冶金工程—冶金物理化学]