2-7. High throughput hot isostatic pressing micro-synthesis for bulk combinatorial materials of high entropy alloys

Zhao Lei, Yang Lixia，Liu Bin，Wang Hui，Huang Zaiwang，Chen Xuebin，Wang Haizhou

 1. Central Iron & Steel Research Institute，2. Beijing Key Laboratory of Metal Materials Characterization，

3. Central South University，4. University of Science & Technology Beijing

Abstract:High throughput synthesis is an important part of Material Genome Engineering (MGE). MGE changed the traditional sequential iteration method to parallel processing so a large number of materials can be prepared and screened in a short time. For examples, a combinatorial materials chip with 128 different components on a substrate was synthesized by thin film deposition and physical masking techniques. High-throughput thin film growth technology realized to screen the semiconductor materials with discrete and continuous components successfully. Diffusion multiple approach was used to measure phase diagrams and diffusion dynamics data quickly. Laser additive manufacturing technology was used to prepare binary and ternary Ti-based alloys and Fe-based gradient alloys. High-throughput Jominy end quenching technique was to synthesize a superalloy with gradient distributing γ' phase. high-throughput preparation device for multi-component gradient metal materials was used to prepare alloy rod composed of multiple components including Al, Zn, Mg and Cu continuously gradient distributing lengthwise. In a word, high-throughput synthesis technique has grown mature with respect to thin films and functional materials, but still remained in its infancy with respect to bulk materials. For the purpose of improving R&D and efficient applications, it is imperative to develop more types of high-throughput synthesis techniques for bulk materials.

       For the first time, a novel high-throughput Hot Isostatic Pressing (HIP) micro-synthesis of bulk combinatorial materials based on the theories of powder metallurgy and thermal diffusion is studied. HIP, which is based on sintering and densification of samples under high temperature and pressure, has the characteristics of fast sintering speed, high compaction density, good thermal diffusivity, short production cycle and low material loss. It is an important means of powder metallurgy for the same alloys and an important process for diffusion welding of dissimilar alloys. In our research, we designed a structural container with a honeycomb array of internal housing by addictive manufacturing to isolate different proportions metal powders. Then the honeycomb array was put into a steel sleeve to produce a bulk combinatorial material with various discrete components by HIP. and prepared a combinatorial material containing 85 different FeCrCoNi-type HEAs via combinatorial design. 13 kinds of pure spherical powders including Fe, Cr, Co, Ni, Mo, Mn, W, Si, Nb, Ti, Ta, Cu, Al were used to design 85 HEAs mixture powders. Then the powders were filled into honeycomb-array cells after being mixed for 24hrs by high throughput mixing machine made by Central South University. Three honeycomb sleeves were prepared respectively in 800°C，1000°C，1200°C for 2hrs under 150MPa pressure. The samples were analyzed by means of micro-XRF, micro-XRD, full-field metallography, high-throughput SEM and microhardness. The results show that the pure Ti honeycomb-array of the bulk combinatorial material is arranged regularly and clearly. The components in the discrete honeycomb cells are consistent with the design and form a high-density solid solution phase. The microhardness of Fe-Co-Cr-Ni-Cux and Fe-Co-Cr-Ni-Alx systems is the lowest, while that of Fe-Co-Cr-Ni-Six, Fe-Co-Cr-Ni-Mox and Fe-Cr-Co-Ni-Si-Ta systems is the highest. In future, we will further optimize the HIP conditions and simulate the honeycomb-array with finite element to improve high-throughput HIP micro-synthesis technique.
Keywords:high-through; micro-synthesis; hot isostatic pressing; honeycomb array; bulk combinatorial materials; high entropy alloys

     高熵合金块体组合材料的热等静压高通量微制造

赵雷, 杨丽霞，刘彬，王辉，黄再旺，陈学斌，王海舟*
1 钢铁研究总院，2 金属材料北京市重点实验室，3 中南大学，4 北京科技大学 

摘要:高通量制备技术是材料基因工程的重要组成部分，其将传统的顺序迭代方法改为并行处 理，可实现在短时间内完成大量样品的制备和筛查。例如:薄膜沉积掩膜技术是在一块基片上 合成 128 种不同组分的“组合材料芯片”;高通量薄膜生长技术实现分立及连续组分半导体材料 的筛选;扩散多元节方法实现相图和扩散动力学数据的快速测定;激光增材制造方法制备了二 元及三元的钛基和铁基梯度合金;高通量热处理技术实现在一块镍基高温合金材料中合成梯度 分布的γ'相;多组分梯度金属材料高通量制备装置实现了 Al、Zn、Mg、Cu 沿长度方向成分连续梯度分布的多组元合金棒。目前，高通量制备技术在薄膜材料和功能材料方面发展比较成熟， 但在块体类的结构材料方面尚处于起步阶段，亟需开发更多类型的块体材料高通量制备技术， 以提高结构材料的研发应用效率。

图 1 高通量热等静压微制造的块体组合材料

      本研究基于粉末冶金及热扩散原理，首次实现并开发多组分块体组合材料的热等静压高通量微制造技术。热等静压基于高温和高压作用下样品的烧结和致密化成型，具有烧结速度快、 压制致密度高、热扩散性好、生产周期短、材料损耗小等特点，是同种合金的粉末冶金重要手 段，也是异种合金表面扩散焊接的重要工艺。本研究采用增材制造技术设计了一个由纯钛金属 制成的蜂巢阵列，用以隔离每个蜂巢孔里填装的不同配比的金属混粉，再将蜂巢阵列放入钢制 外包套，经热等静压一次成型制备出一块具有多种分立式组分的块体组合材料。实验选用 Fe, Cr, Co, Ni, Mo, Mn, W, Si, Nb, Ti, Ta, Cu, Al 共 13 种纯金属作为研究对象，分别按 1:1 的原子比配比 成 85 种不同组分的混合金属粉，以期高通量制备不同组分的 Fe-Co-Cr-Ni 系的高熵合金，采用 中南大学设计的高通量机械混粉装置混合 24 小时，将混合粉填实到蜂巢孔中密封抽真空后，分别在 800°C，1000°C，1200°C下等静压 2 小时，作用压力均为 150MPa。采用微束 XRF、微束 XRD、全视场金相、高通量扫描电镜、高通量显微硬度等检测手段对样品进行分析，结果表明， 块体组合材料的纯钛蜂巢阵列排布规则且清晰可见，各分立蜂巢孔内组分与设计相符且形成高 密度的固溶体合金相。经筛查，含 Fe-Co-Cr-Ni-Cux 和 Fe-Co-Cr-Ni-Alx 系的材料显微硬度最低， 含 Fe-Co-Cr-Ni-Six，Fe-Co-Cr-Ni-Mox 和 Fe-Cr-Co-Ni-Si-Ta 系的材料显微硬度最高。后期实验将 进一步优化热等静压条件及采用有限元方法模拟蜂巢阵列包套设计模型，以完善热等静压高通 量微制造技术。

关键词:高通量;微制造;热等静压;蜂巢阵列;块体组合材料;高熵合金