激光3D打印制备模具材料CrMoTi中熵合金

PREPARATION AND ELECTROCHEMICAL BEHAVIOR CHARACTERIZATION OF TRANSITION METAL OXIDE ANODE MATERIALS

李婵

11849243

硕士

材料工程

严明

2020-05-30

2020-07-01

哈尔滨工业大学

深圳

多主元合金作为一种新兴的合金材料，因其具有高强度、高硬度、良好的高温稳定性、抗氧化性和耐腐蚀性等独特的优异性能，近年来得到快速发展，已然成为金属材料领域新兴的研究热点。目前，多主元高熵合金材料及其增材制造技术的研究处在发展初期。根据现有研究表明，部分三元或四元的多主元合金的性能与五元的多主元合金性能相当，甚至优于五元的多主元高熵合金。此外，目前对多主元合金的加工工艺多以传统的真空电弧熔炼技术为主，但是该制备技术存在成形形状简单、成形尺寸有限、容易发生成分偏析、缩孔缺陷等不足，从而限制了其在多主元合金复杂成形构件的制备方面的应用。因此，尝试采用增材制造技术制备性能优异的多主元合金具有较大的科研意义。本课题在完成对 CrMoTiAlx（x = 0，0.1，0.2，0.3，0.4）合金体系的理论计算的基础上，采用传统的真空电弧熔炼 技 术 对 CrMoTiAlx （ x =0，0.1，0.2，0.3，0.4）合金体系进行制备，分别采用激光 3D 打印技术中的金属熔融沉积以及激光选区熔化对经过机械混合元素粉体方法的 CrMoTi 三元中熵合金进行打印参数的优化。针对 CrMoTiAlx（x = 0，0.1，0.2，0.3，0.4）合金体系，系统研究了其物相组成、微观组织、元素分布、显微硬度及压缩性能，综合分析了 Al 元素含量的增加对 CrMoTi 合金组织性能的影响规律。研究得到以下结论：铸态 CrMoTiAlx（x = 0，0.1，0.2，0.3，0.4）合金由 BCC 固溶体相和少量的 β-Ti 相组成。当x = 0.3时，CrMoTiAl0.3 合金具有最高的显微硬度，为643.3 HV0.3，当x = 0.2时，CrMoTiAl0.2 合金具有最高的抗压强度，为 1120 MPa，对应的应变为 6.0%。随着 Al 元素含量的增加，合金的显微硬度和抗压强度均先增加后减小。在研究铸态 CrMoTiAlx（x = 0，0.1，0.2，0.3，0.4）合金体系的基础上，本课题进一步研究利用激光 3D 打印技术制备 CrMoTi 三元中熵合金的可行性。通过两种不同工作原理的 3D 打印技术——金属熔融沉积与激光选区熔化制备CrMoTi 三元中熵合金，研究两种打印方式所得样品的物相组成、微观组织、元素分布、显微硬度，并探究不同打印参数对致密度的影响，优化打印工艺参数窗口。

As a burgeoning alloy system, multi-principal elements alloys have developed rapidly and become the research hotspot in the field of metal materials in recent years due to its unique advantages in terms of strength, hardness, phase stability, oxidationresistance, corrosion resistance, etc. Currently, the research on multi-principal elements alloys and the additive manufacturing technology to fabricate them are in nascent stage. The existing research shows that the properties of some ternary or quaternary multi-component alloys are comparable to, or even better than those of quinary multi-component alloys. In addition, vacuum arc melting is the main processing technology to fabricate multi-principal elements alloys. However, thetechnology restricts the practical application of multi-principal elements alloys with the limitations on geometry complexity and forming size, together with the component segregation and shrinkage defects. Therefore, it is of great significance toattempt to prepare multi-principal elements alloys with excellent performances byadditive manufacturing.This study, based on the theoretical calculation of CrMoTiAlx( x = 0, 0.1, 0.2, 0.3, 0.4) alloy system, was conducted to research the cast CrMoTiAlx(x = 0, 0.1, 0.2, 0.3, 0.4) alloy system fabricated by vacuum arc melting and the printingparameters of CrMoTi ternary medium-entropy alloy fabricated by direct laser deposition and selective laser melting respectively with the elemental powder blends as the raw materials. The CrMoTiAlx(x = 0, 0.1, 0.2, 0.3, 0.4) alloy system was studiedsystematically about its phase composition, microstructure, element distribution, microhardness and compressive properties in order to figure out the influence law of Al element content in the alloy system. This study showed that the as-cast CrMoTiAlx( x = 0, 0.1, 0.2, 0.3, 0.4 ) consists of body-centered cubic (BCC) solid solution and a small amount of β-Ti phase. As x = 0.3, CrMoTiAl0.3 alloy had the largest microhardness of 643.3 HV0.3. As x = 0.2, CrMoTiAl0.2 alloy had the largest compression strength of 1120 MPa and the corresponding fracture strain of 6.0%. With the increase of Al content, the microhardness and compressive strength of the alloy system were found to increase first and then decrease.Based on the study of the as-cast CrMoTiAlx( x = 0, 0.1, 0.2, 0.3, 0.4 ) alloy system, the research on the feasibility of preparing CrMoTi ternary medium-entropy alloy by laser 3D printing was further conducted. The CrMoTi ternary mediumentropy alloy was prepared by two different working principles of 3D printing—direct laser deposition (DLD) and selective laser melting (SLM). The phase composition, microstructure, element distribution, microhardness and the influence of the printing parameters on the forming density of the samples obtained by two above printing methods were studied, and the printing parameters were optimized.

中熵合金 3D 打印 金属熔融沉积 激光选区熔化 元素粉体混合

medium-entropy alloys 3D printing direct laser deposition selective laser melting elemental powder blends

中文

联合培养

南方科技大学

李婵. 激光3D打印制备模具材料CrMoTi中熵合金[D]. 深圳. 哈尔滨工业大学,2020.