A Study on Internal Defects of PREP Metallic Powders by Using X-ray Computed Tomography

Area of Science:

• Materials Science
• Powder Metallurgy
• Additive Manufacturing

Background:

• The plasma rotating electrode process (PREP) is crucial for producing high-quality metal powders.
• Understanding internal defects in PREP powders is essential for optimizing manufacturing processes.
• Ti-6Al-4V, 316-steel, and Co-29Cr-6Mo alloys are widely used in demanding applications.

Purpose of the Study:

• To characterize internal defects in PREP-produced powders of Ti-6Al-4V, 316-steel, and Co-29Cr-6Mo alloys.
• To investigate the influence of rotation speed and particle size on defect formation.
• To determine the effect of alloy composition on internal pore characteristics.

Main Methods:

• Powder samples produced via plasma rotating electrode process (PREP) at various rotation speeds.
• Scanning Electron Microscopy (SEM) for high-resolution surface and cross-sectional analysis.
• Synchrotron X-ray Computed Tomography (CT) for non-destructive internal defect characterization.

Main Results:

• Internal pores form more readily in coarse particles compared to fine powders within the same alloy.
• Increasing the rotation speed during PREP can effectively reduce the proportion of powder containing pores.
• Alloy composition significantly impacts the formation and characteristics of internal defects.

Conclusions:

• Particle size and PREP rotation speed are key controllable factors influencing internal porosity in alloy powders.
• Alloy composition plays a critical role in the susceptibility to internal defect formation during PREP.
• Optimizing PREP parameters based on alloy type and desired powder characteristics is vital for defect mitigation.