Investigating relationships between laser metal deposition deployment conditions and material microstructural evolution

Project aim

The overall aim is to establish correlations between the microstructural evolution of LMD materials and varying LMD deployment parameter inputs. Understanding the correlations affords the ability to control mechanical properties such as surface roughness, density, hardness, yield strength, and ultimate tensile strength through material composition selection.

Project background

Laser metal deposition (LMD) as a form of additive manufacturing has provided a new and unique method for manufacturing a wider range of components when compared to traditional subtractive methods. LMD can be utilised for the repair and remanufacture of metallic components with reduced replacement costs and with the potential for better mechanical and wear resistance properties ensuring remanufactured components are better than or equal to originals.

The primary attraction for AM is the ability to create components with materials, geometries, complexity, accuracy, and programming which would previously have been extremely difficult or impossible with traditional methods. It has long been established that the primary factor in determining material microstructure evolution is cooling rates, which are substantially affected by scanning path speed (mm/min) and toolpath geometry. Further studies have shown considerable material microstructural variance depending on laser power (W), scan speed (mm/ min), layer thickness (μm), overlap percentage (%), and flow rate (g/min) input parameters.