Effect of precipitation-forming elements in a near-eutectic Al-Ce alloy for Laser Powder Bed Fusion

Abstract

Despite a growing interest in additive manufacturing technologies, there is still a limited selection of suitable materials developed regarding the unique non-equilibrium cooling conditions. A highly promising alloy system for Laser Powder Bed Fusion (LPBF) is Al-Ce, which shows outstanding processability in recent studies. The medium strengths already achievable with the binary system are to be improved in these investigations by additional precipitation-forming elements. By adding Mg and Si, a very high tensile strength of 593 MPa in the as-built condition can be achieved. XRD measurements show that the addition of these two elements lead to additional formation of an AlCeSi phase and phases of the Mg 2 Si precipitation sequence, which affects the usually expected eutectic formation of the Al 11 Ce 3 phase. Contrary to the expected dominance of the binary intermetallics, AlCeSi in particular can be identified. The Al 11 Ce 3 content in the microstructure can only be significantly increased with modified parameter combinations or volume energy inputs. Along with this, additional differences in grain size and grain morphology can be identified by EBSD investigations. The influence of the parameters extend to different mechanical properties as a function of the applied parameter combinations. With the very good additive processability in the form of wide process parameter windows, the parameter combinations can be used to adjust the properties in the as-built state.