Spark Plasma Sintering of AlN/Al Functionally Graded Materials.

Area of Science:

• Materials Science
• Composite Materials
• Nanotechnology

Background:

• Gradient materials offer tailored properties by varying composition across layers.
• Aluminum nitride/aluminum (AlN/Al) composites are promising for thermal management applications.
• Controlling microstructure and properties in gradient composites is key for performance.

Purpose of the Study:

• To investigate the effect of sintering temperature and holding time on AlN/Al gradient composites.
• To characterize the microstructure and mechanical properties of the developed gradient composites.
• To evaluate the potential of these composites for reducing thermal stress in electronic modules.

Main Methods:

• Six-layer AlN/Al gradient composites were fabricated using spark plasma sintering (SPS).
• Microstructure was analyzed to confirm bonding and gradient distribution.
• Mechanical properties, including hardness and coefficient of thermal expansion (CTE), were measured.

Main Results:

• Sintering parameters influenced the microstructure and properties of the AlN/Al composites.
• A gradient in hardness and CTE was observed, correlating with AlN volume fraction.
• Optimal conditions yielded a maximum hardness of 1.25 GPa and a minimum CTE of 13-14 ppm/K at 45% AlN.
• Simulations confirmed that the gradient design effectively mitigates thermal stress in transmitter and receiver (T/R) modules.

Conclusions:

• Spark plasma sintering is effective for producing AlN/Al gradient composites with tailored properties.
• The gradient structure significantly improves thermal stress management capabilities.
• These findings provide experimental validation for preparing advanced gradient Al matrix composites.