异构结构纳米金刚石/钛基复合材料的微观组织与力学性能

目的 探究不同粗细晶比例的异构结构对纳米金刚石/钛基复合材料的物相组成、组织结构及力学性能的影响.方法 首先利用低能与高能球磨机进行粉末混合,接着利用放电等离子烧结技术对复合材料进行制备,最后采用金相显微镜、XRD、SEM、TEM、显微硬度计、材料力学电子万能试验机对复合材料的形貌、成分及力学性能进行分析.结果 复合材...

Microstructure and Mechanical Properties of Nanodiamond/Titanium Matrix Composites with Heterogeneous Structure

The paper investigates the effect of heterogeneous structure with different ratio of coarse to fine crystal on phase composition, microstructure and mechanical properties of nanodiamonds reinforced titanium matrix composites. Methods are shown below:First, the powder was mixed by low and high energy ball milling, and then the composites were prepared by spark plasma sintering technique. Finally, the morphology, composition and mechanical properties of the composites were analyzed by optical microscopy, XRD, SEM, TEM, microhardness tester and electronic universal mechanical testing machine. Experimental results show that nano-TiC phase is formed in the composite material, fine/coarse heterogeneous structure and the composition concentration gradient distribution of the reinforcing phase are formed in the microstructure. With the gradual increase of the proportion of fine grains, the hardness and strength are gradually enhanced, the hardness is up to 382HV, and the tensile yield strength is up to 1017 MPa with ductility of 17.8%. The addition of ND and heterogeneous structure makes the strength and hardness of the composites significantly improved, while the ductility loss is small. Titanium matrix composites with heterogeneous structure have excellent combination of strength and ductility. The strengthening and toughening mechanism is the hinder and pinning effect of dislocation movement by controllable non-uniform distribution of nanodiamonds and TiC reinforcements.