C ast irons are among the most widely used metallic materials due to their good mechanical and physical properties, excellent casting ability and low cost. According to the survey of Modern Casting [1] , as shown in Fig. 1, outputs of lamellar graphite cast iron (LGI) are much higher than that of spheroidal graphite cast iron (SGI) though SGI has better mechanical properties. One of the reasons is that LGI has wide applications at high temperatures due to its superior thermal conductivity. That's why the LGI and compacted graphite cast iron (CGI) are widely applied in brake disc, engine block and cylinder head [2][3][4][5] . The thermal conductivity is an extremely important performance index for cast irons. The high thermal conductivity can help to transfer heat rapidly and prevent thermo-mechanical fatigue, deformation and hot cracking, thereby ensuring the applications of cast irons in more complex or harsher conditions and improving the service life of products [6] . Therefore, on the premise of basic mechanical properties, the design and development of high thermal conductivity cast irons is one of the key points in the research and development of cast irons.Cast irons are multi-component alloys with regular elements of C and Si and some commonly added alloying elements, such as Mn, Cu, Ni, Cr, W, Mo, V, Ti, Al, etc. The microstructure of cast irons is complicated, usually composed of ferrite, pearlite, graphite, and cementite. So, the thermal conductivity of cast irons is dependent on both the alloying elements and structural constituents.During solidification, the formation of cast iron microstructure, especially the graphite morphology, is governed by the difference in thermal conductivity between graphite and austenite in eutectic couple, and between different orientations of graphite crystals [7] . According to different graphite morphologies, cast irons where carbon precipitated in the form of graphite (graphite cast irons) are mainly divided into LGI with lamellar graphite, CGI with compacted graphite and SGI with spheroidal graphite. Generally, the thermal