选区激光熔化制备块体TiC/Ti纳米复合材料的成形工艺及性能  

Forming Process and Properties of TiC/Ti Bulk-Form Nanocomposites Prepared by Selective Laser Melting

作　　者：孟广斌[1] 顾冬冬[1] 李闯[1] 沈以赴[1] 李玉芳[1] 

机构地区：[1]南京航空航天大学材料科学与技术学院,江苏南京210016

出　　处：《中国激光》2011年第6期219-225,共7页Chinese Journal of Lasers

基　　金：国家自然科学基金(51054001);江苏省自然科学基金(BK2009374);航空科学基金(2010ZE52053);南京航空航天大学基本科研业务费专项科研项目(NS2010156)资助课题

摘　　要：利用选区激光熔化(SLM)工艺成功制备了TiC增强Ti基纳米复合块体材料,其中TiC质量分数为30%。研究了激光线能量密度η(激光功率与扫描速率之比)对SLM成形试件的表面形貌、致密度、微观组织及力学性能的影响。结果表明,在η=400 J/m时,SLM成形试件表面较为光滑,成形致密度达到95.5%,平均显微硬度为750 HV,增强体TiC以细小层片状纳米结构均匀分布于Ti基体中。摩擦磨损试验表明,激光成形复合材料的摩擦系数为0.2,远低于SLM纯钛成形件(摩擦系数为1.2)。在较高激光线能量密度下(800 J/m),因热裂纹产生和增强体TiC枝晶粗化,致使复合材料致密度、显微硬度及磨损性能下降。The TiC（mass fraction of 30%） reinforced Ti matrix bulk-form nanocomposites are successfully prepared by selective laser melting（SLM） process.The influence of the applied laser linear energy density η（the ratio of laser power to scan speed） on surface morphology,densification level,microstructure,and mechanical performance of SLM-processed parts is studied.It shows that when η is 400 J/m,the SLM-processed part has a relatively smooth surface.A high relative density of 95.5% and an average microhardness of 750 HV are obtained.The TiC reinforcing phase is dispersed uniformly in the Ti matrix,exhibiting an ultrafine lamellar nanostructure.The dry sliding wear tests reveal that the TiC/Ti nanocomposites possess a considerably low friction coefficient of 0.2,which is much lower than SLM-processed pure titanium parts of 1.2.The densification rate,microhardness,and wear performance decrease at a higher laser energy density of 800 J/m due to the formation of thermal cracks and the coarsening of TiC dendritic reinforcing phase.

关 键 词：激光技术 快速成形 选区激光熔化 纳米复合材料 显微硬度 磨损 

分 类 号：TG14[一般工业技术—材料科学与工程] TG665[金属学及工艺—金属材料]