TiB_2增强Al-Si复合材料激光增材制造工艺及性能研究

Study on Manufacturing Processes and Properties of TiB_2 Reinforced Al-Si Composite by Laser Additive Manufacturing

采用激光立体成形(LSF)和激光选区熔化(SLM)两种激光增材制造工艺制备得到原位自生Ti B2/Al-Si复合材料,对其微观组织和力学性能展开了研究,探索不同激光增材制造工艺对铝基复合材料组织的作用,并分析其微观组织对宏观力学性能的影响机制。结果表明,LSF试样由于热量积累导致Si呈块状析出,部分Ti B2颗粒熔化生成针状的Al3Ti相;而在SLM试样中,网格状Si及纳米级Ti B2颗粒弥散分布在基体之中,晶粒尺寸在200 nm^1μm之间,表现为粗晶区和细晶区交替出现的组织结构,无副相生成。除此之外,与LSF试样相比,SLM试样密度提高约2.8%,硬度有了明显的提升,稳定在130~135 HV之间。因此,现阶段SLM技术更加适合用于原位自生Ti B2/Al-Si复合材料的激光增材制造。

In-situ TiB2/Al-Si composite was successfully fabricated by laser solid forming （LSF） and selective laser melting （SLM）, and the microstructure and mechanical properties of the composite were studied. The effect of different laser additive manufacturing processes on the microstructure of the Al matrix composite was discussed, and the influence mechanism of microstructure on mechanical properties was also analyzed. The results indicate Si separates out as bulk precipitation due to heat accumulation in LSF sample, and particle TiB2 remelts to form acicular Al3Ti phase. However, in SLM sample, Si in net-shape and TiB2 particles at nanoscale disperse in the matrix evenly, and the microstructure is greatly refined with grain size ranging from 200 um to 1μm. Coarse grain zone and fine grain zone appear alternately without other phases. Moreover, compared to LSF sample, the density of SLM sample increases by about 2.8%, and hardness of the sample is also greatly improved, about 130-135 HV. Therefore, SLM is more suitable for laser additive manufacturing of in-situ TiB2/Al-Si composite at present.