Liquid metal infiltrated interpenetrating composites based on bulk metallic glass - processing, characterization and modeling

以大块金属玻璃（BMG）为增强材料的金属基复合材料在弹性比能吸收能力、硬度和强度方面都有很大的发展潜力。BMG的缺点是易脆性断裂，韧性低。在这方面，bmg -泡沫的潜力已经可以显示出来，因为泡沫腹板的坍塌大大增加了压缩载荷下的塑性。过去已经成功生产了bmg泡沫。到目前为止，bmg泡沫与金属基体结合形成MMC还没有发生。因此，该项目的目的是研究由BMG制成的三维互穿结构的mmc。通过将BMG成功地嵌入金属基体中，可以获得良好的增强效果。本申请涉及具有三维BMG互穿结构的mmc的加工和材料表征。由于BMG的承载功能，与传统的0维（颗粒）或1维和2维增强材料（带状）相比，互穿结构有望改善复合材料的力学性能。更高的力学性能，特别是在压缩载荷下，因为泡沫腹板的崩溃导致更高的塑性。本应用计划的BMG泡沫处理是通过BMG和盐颗粒的模压热压来实现的。后者在随后的处理步骤中被冲洗掉。用这种方法制备的开孔bmg -泡沫，随后用铝进行气压渗透。申请人的初步工作表明，BMG Ni60Nb20Ta20具有较高的结晶温度（969 K），具有很好的玻璃化倾向，硬度和强度都很高。结晶温度明显高于共晶铝合金AlSi12的熔化温度，从而实现了基于Ni60Nb20Ta20三维网络的MMC的熔体冶金加工。通过力学和微观结构表征方法研究渗透过程参数的变化和过程-结构-性能的关系。除了二维和三维微观结构分析外，所使用的方法还包括通过UPS确定弹性性能，进行（原位）和非（非原位）同时分析损伤行为的力学试验。此外，还将确定热膨胀系数和热机械载荷对复合材料结构和性能的影响。

Metal matrix composites (MMCs) with reinforcements of bulk metallic glass (BMG) have great potential in terms of elastic-specific energy absorption capacity, hardness and strength. The susceptibility to brittle fracture and low toughness is a disadvantage of BMG. In this regard, the potential of BMG-foams could already be shown, as the plasticity under compressive loads is significantly increased due to the collapse of the foam webs. BMG-foams have already been successfully produced in the past. The combination of a BMG-foam with a metal matrix to form a MMC has not taken place so far. The aim of the project is therefore the investigation of MMCs with a three-dimensional, interpenetrating structure made of BMG. A good reinforcing effect can be achieved, by successfully embedding BMG into a metallic matrix. The present application involves the processing and materials characterization of MMCs with a 3-dimensional BMG interpenetrating structure. Due to the load-bearing function of BMG, the interpenetrating structure is expected to improve the mechanical properties of the composite compared to conventional 0- (particle) or 1- and 2- dimensional reinforcements (ribbons). Higher mechanical properties can be achieved especially under compressive loads, because the collapse of the foam webs leads to higher plasticity. The BMG-foam processing planned in the present application is realized by means of die hot pressing of BMG and salt particles. The latter being washed out in a subsequent process step. The open-pore BMG-foam produced in this way is infiltrated by means of gas pressure infiltration with aluminum afterwards. Preliminary work of the applicant has shown that the BMG Ni60Nb20Ta20 has a relatively high crystallization temperature (969 K) coupled with very good glass-forming tendency and high hardness and strength. The crystallization temperature is thus significantly higher than the melting temperature of the eutectic aluminum alloy AlSi12, which enables a melt-metallurgical processing of an MMC based on a 3-dimensional network of Ni60Nb20Ta20. Process parameters of the infiltration are to be varied and the process-structure-property relationships are to be investigated by means of mechanical and microstructural characterization methods. In addition to the 2- and 3-dimensional microstructure analysis, the methods used include the determination of the elastic properties by means of UPS, mechanical tests with (in-situ) and without (ex-situ) simultaneous analysis of the damage behavior. Furthermore, the thermal expansion coefficient and the influence of thermal-mechanical loads on the structure and properties of the composite are to be determined.