Microstructure and Mechanical Characterization of Novel Al

Area of Science:

• Materials Science
• Ceramic Engineering
• Metallurgy

Background:

• Ceramic-intermetallic composites offer unique properties for demanding applications.
• Understanding the link between microstructure and mechanical performance is crucial for material design.
• Powder metallurgy techniques, like Plasma Pressure Sintering (PPS), are used for fabricating advanced composites.

Purpose of the Study:

• To investigate the relationship between the microstructure of Al2O3-NiAl composites and their mechanical properties.
• To determine the effect of sintering temperature and compo-powder content on composite characteristics.
• To evaluate hardness, fracture toughness (KIC), and wear resistance.

Main Methods:

• Fabrication of six series of Al2O3-NiAl composites using the PPS technique.
• Microstructural analysis via Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray Spectroscopy (EDS) and X-ray Diffraction (XRD).
• Mechanical property testing including hardness, fracture toughness (KIC), and wear resistance (ball-on-disc).

Main Results:

• Composite density increased with higher sintering temperatures.
• Hardness reached a maximum of 20.9 ± 0.8 GPa at 1300 °C with 2.5 vol.% compo-powder.
• The highest fracture toughness (KIC) of 8.13 ± 0.55 MPa·m0.5 was also observed for composites sintered at 1300 °C (2.5 vol.% compo-powder).
• Average friction coefficient ranged from 0.8 to 0.95 against Si3N4.

Conclusions:

• Sintering temperature significantly influences the density and mechanical properties of Al2O3-NiAl composites.
• Optimal processing conditions (1300 °C, 2.5 vol.% compo-powder) yield enhanced hardness and fracture toughness.
• The study provides valuable insights into tailoring ceramic-intermetallic composites for improved performance.