Bolibruchová Dana, Širanec Lukáš, Matejka Marek
Department of Technological Engineering, Faculty of Mechanical Engineering, University of Zilina, Univerzitná 8215/1, 010 26 Žilina, Slovakia.
Materials (Basel). 2022 Jul 8;15(14):4798. doi: 10.3390/ma15144798.
The aim of this paper was to analyze the impact of the addition of different amounts of zirconium (0.05; 0.10; 0.15 and 0.20 wt. % Zr in the form of the AlZr20 master alloy) on selected properties of AlSi5Cu2Mg aluminum alloy. This is a new alloy for cylinder head castings and has only been used for a relatively short time. The specificity of this alloy is its chemical composition-specifically the low permitted Ti content, which makes it impossible to refine the grain structure of this alloy using standard Al-Ti-B grain refiners. The aim of our ongoing research is to find a suitable alloying element that would positively mainly affect the mechanical and also physical properties of this alloy, which are crucial for complex automotive castings such as cylinder heads. The results of our research showed that increasing zirconium content had no effect on the increase in ultimate tensile strength, yield strength and hardness of as-cast samples. After T7 heat treatment, a more significant increase in UTS, YS and thermal conductivity occurred due to the precipitation of Cu- and Mg-rich strengthening precipitates. Zirconium-rich intermetallic phases were observed in the shape of separate thick needles or as a cluster of two crossed thinner needles. SEM observations showed that these phases crystallized near to the intermetallic phases based on Cu and Fe. Increasing the Zr content was accompanied by an increase in liquidus temperature, the density index and the area fraction of porosity values.
本文旨在分析添加不同量的锆（以AlZr20中间合金形式存在的0.05%、0.10%、0.15%和0.20%重量百分比的Zr）对AlSi5Cu2Mg铝合金某些性能的影响。这是一种用于气缸盖铸件的新型合金，使用时间相对较短。该合金的特性在于其化学成分，特别是允许的低Ti含量，这使得无法使用标准的Al-Ti-B晶粒细化剂细化该合金的晶粒结构。我们正在进行的研究目的是找到一种合适的合金元素，该元素将主要对这种合金的力学性能和物理性能产生积极影响，而这些性能对于诸如气缸盖之类的复杂汽车铸件至关重要。我们的研究结果表明，增加锆含量对铸态样品的极限抗拉强度、屈服强度和硬度的增加没有影响。经过T7热处理后，由于富Cu和Mg的强化析出相的析出，UTS、YS和热导率有更显著的增加。观察到富锆金属间相呈单独的粗针状或两个交叉的细针簇状。扫描电子显微镜观察表明，这些相在基于Cu和Fe的金属间相附近结晶。增加Zr含量伴随着液相线温度、密度指数和孔隙率值面积分数的增加。
