Sintering mechanics of binder jet 3D printed ceramics treated with a reactive binder
Sintering mechanics of binder jet 3D printed ceramics treated with a reactive binder
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DOI：
10.1016/j.jeurceramsoc.2022.12.017
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发表时间：
2022-12
影响因子：
5.7
通讯作者：
Lynnora O. Grant;C. Higgs;Z. Cordero
中科院分区：
文献类型：
--
作者：
Lynnora O. Grant;C. Higgs;Z. Cordero
反应性粘结剂通过析出强化颗粒间接触的固相来减少粘结剂JET 3D打印组件在烧结过程中的变形。本工作将实验与微观力学模型相结合，旨在阐明反应性粘结剂钛双铵盐(TALH)在粘结剂喷印二氧化钛烧结过程中对蠕变和致密化的影响。对印刷材料进行TALH处理后，会在微米级的颗粒上覆盖一层纳米二氧化钛。在烧结温度下，这种覆盖层通过颗粒生长被消耗，因此经Talh处理的材料和整齐的材料的结构看起来几乎相同。在TALH处理的材料中的蠕变速率比印刷的TiO2中的慢，但在相同的相对密度下，处理的材料中的蠕变速度更快。纯钛和纯钛均表现出扩散蠕变，应力指数接近1，活化能为400kJ/∼。烧结粉骨料的结构演化模型表明，TALH对烧结力学的主要作用是增加颗粒间的接触尺寸，而配位数基本不变。这些见解被用来开发设计活性粘结剂以减轻蠕变的通用指南，定量地强调了粘结剂分解产生的高固体产率的好处。
Reactive binders mitigate distortion during sintering of binder jet 3D printed components by precipitating a solid phase that reinforces interparticle contacts. The present work combines experiments with micromechanical modeling to clarify how aqueous titanium bis-ammonium lactato dihydroxide (TALH), a reactive binder, affects creep and densification during sintering of binder jet printed TiO2. TALH treatment of as-printed material results in a nanocrystalline TiO2overlayer that coats the micron-scale particles. At sintering temperatures, this overlayer is consumed via grain growth such that the structures of the TALH-treated and neat materials appear nearly identical. Creep rates are slower in the TALH-treated material than in the as-printed TiO2, but creep in the treated material is faster when compared at equivalent relative density. TALH-treated and neat TiO2both exhibit diffusional creep, with stress exponents near unity and activation energies of ∼400 kJ/mol. Models of structural evolution in sintering powder aggregates show that the dominant effect of TALH on the sintering mechanics is to increase the interparticle contact size, while the coordination number remains essentially unchanged. These insights are used to develop generalized guidelines for designing reactive binders to mitigate creep, quantitatively highlighting the benefits of a high solid yield from binder decomposition.