High alloyed Si ferritic ductile irons can offer potential benefits because they combine high strength, ductility at room temperature, and low oxidation rate at high temperature. However, there is one known drawback and that is these cast irons have limited performance during thermal cycling due to a significant drop of ductility at warm temperatures. This decrease in ductility has been linked to poisoning ferrite grain boundaries by Mg. Therefore, thermodynamic simulations were used to identify altering additions which were able to meditate this negative effect by forming intermetallic phases with Mg. To verify thermodynamic predictions, three alloys were cast including a base and two high Si ductile irons with additions of P and Sb. High-temperature performance of these alloys was experimentally verified including tensile properties at warm temperatures (350–550 °C), oxidation in air at temperatures (700–800 °C), and thermal cycling between 300 and 800 °C. SEM and TEM analyses confirmed that the studied additions reacted with Mg forming different compounds which could prevent poisoning ferrite grain boundaries and improve high-temperature performance of high Si ductile iron.

高合金硅铁素体球墨铸铁可以提供潜在的好处，因为它们兼具高强度，室温下的延展性和高温下的低氧化率。然而，存在一个已知的缺点，即这些铸铁由于在热温度下的延展性显着下降而在热循环期间具有有限的性能。延展性的下降与镁导致的铁素体晶界中毒有关。因此，使用热力学模拟来识别可改变的添加物，这些添加物能够通过与Mg形成金属间相来消除这种负面影响。为了验证热力学预测，铸造了三种合金，包括贱金属和两种高Si球墨铸铁，并添加了P和Sb。这些合金的高温性能已通过实验验证，包括在温暖温度（350–550°C）下的拉伸性能，在温度（700–800°C）下在空气中的氧化以及300至800°C之间的热循环。SEM和TEM分析证实，所研究的添加剂与镁反应生成不同的化合物，可以防止铁素体晶界中毒并改善高硅球墨铸铁的高温性能。