Abstract

Science and technology of materials are widely interested in the development of new alloys involving tungsten due to its large applicability to the domain of nuclear material transportation. Tungsten is a refractory material and it has many applications in the nuclear industry due to its mechanical properties and excellent cross-section for thermal neutrons, being widely used for shielding of high-energy radiation. Some of the main elements added to tungsten forming alloys are Nb, Cr, Cu, Fe, Ni, Mo, Co, Sn, Ti, and Ta, which are responsible for modifications of the physical and chemical properties of the resulting alloy, interfering on the attenuation of gamma radiation. The main goal of this paper is to present a refractory alloy based on tungsten with embedded infiltrating elements like copper (Cu) and nickel (Ni) and characterize the microstructural evolution of different sintering process during its formation. Such a refractory alloy is submitted to the following characterization process: X-rays diffractometry, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy, and energy dispersive spectroscopy. The diffractometry exhibit typical standard results for the precursor powders: W, Cu, and Ni demonstrating high degrees of purity accordingly to the crystallographic determined parameters. The TGA for the powder W demonstrated thermal stability until 360 ºC, after an increase of mass due to the process of oxidation. The DSC analyze present two endothermal processes at temperatures 350 °C and 450 °C. The microstructural evolution of WCuNi samples presents the absence of oxidation, homogeneous morphology and stability of the binary phase α–β (W and CuNi respectively) for different sintering. These results shall be taken into consideration for future works, particularly on the study of shielding and gamma radiation attenuation.

Graphic abstract

摘要

材料科学和技术对涉及钨的新合金的开发引起广泛兴趣，因为它在核材料运输领域具有很大的适用性。钨是一种耐火材料，由于其机械性能和热中子的出色横截面，在核工业中有许多应用，被广泛用于屏蔽高能辐射。添加到钨形成合金中的一些主要元素是Nb，Cr，Cu，Fe，Ni，Mo，Co，Sn，Ti和Ta，它们负责改变所得合金的物理和化学性能，从而干扰伽玛射线的衰减。本文的主要目的是提出一种基于钨的耐火合金，具有嵌入的渗透元素，如铜（Cu）和镍（Ni），并表征了其形成过程中不同烧结工艺的微观组织演变。这种耐火合金经过以下表征过程：X射线衍射法，热重分析（TGA），差示扫描量热法（DSC），扫描电子显微镜和能量色散光谱法。衍射法显示出前体粉末：W，Cu和Ni的典型标准结果，从而根据晶体学确定的参数显示出较高的纯度。由于氧化过程导致质量增加后，粉末W的TGA表现出热稳定性直至360ºC。DSC分析显示了在350°C和450°C的温度下的两个吸热过程。WCuNi样品的微观结构演变表明，在不同的烧结条件下，不存在氧化，均相形态和二元相α–β（分别为W和CuNi）的稳定性。这些结果应在以后的工作中加以考虑，尤其是在研究屏蔽和伽马辐射衰减时。

图形摘要