Influence of Graphene‐Based Flux Interlayers on the Microstructure and Properties of Low‐Alloy Steel Fabricated by Cold Metal Transfer‐Based Wire Arc Additive Manufacturing

This study investigates the influence of graphitic flux interlayers on the microstructure, mechanical behaviour, tribological performance, and corrosion resistance of low‐carbon steel fabricated using cold metal transfer‐based wire arc additive manufacturing (CMT‐WAAM). Multi‐layered graphene (MLG) powder was introduced as an interlayer flux between successive deposited layers to fabricate the GR‐IL specimen, while a standard ER70S6 specimen was produced without an interlayer. A systematic comparison was conducted covering microstructural features, mechanical properties, wear behaviour, and corrosion resistance. The MLG interlayer enhanced the deposition process, resulting in grain refinement and improved functional performance. Grain size decreased from 12 to 8 µm, while pearlite content increased from 39.79% to 45.15%, indicating altered phase transformation behaviour. Hardness increased from 178 to 184 HV, improving resistance to plastic deformation. Tensile testing revealed comparable ultimate tensile strength in the horizontal and diagonal orientations, whereas the vertical orientation exhibited lower strength, indicating anisotropy. Pin‐on‐disc testing demonstrated superior tribological performance for the GR‐IL specimen, with a reduced specific wear rate of 2.0 × 10 −6 mm 3 /N·m compared to ER70S6 (4.5 × 10 −6 mm 3 /N·m). Corrosion testing revealed a reduced corrosion rate of 0.07251 mm/year for the GR‐IL specimen compared to 0.07401 mm/year for ER70S6, confirming enhanced corrosion resistance.