The alloy infiltration method (specifically the iron-nickel-based alloy infiltration technique) plays a critical role in improving the compatibility between diamond and binder and enhancing tool life. This is reflected in the following aspects:

1. Improving the Compatibility between Diamond and Binder

 Reducing Thermal Expansion Differences: The alloy infiltration method effectively reduces the thermal expansion difference between the diamond and the binder (metal solvent). This mismatch is a core issue in compatibility, as the large disparity in coefficients of thermal expansion is the primary cause of residual stress within the Polycrystalline Diamond Compact (PDC).

Optimizing Proportion Control: Compared to the traditional powder-mixing method, the alloy infiltration method makes the metal solvent ratio easier to control and offers stronger maneuverability, thereby supplying an adequate proportion between the diamond and the binder.

2. Reducing Residual Stress

 Minimizing Stress Generation: By effectively reducing the difference in thermal expansion coefficients and providing an appropriate binder proportion, this method plays a positive role in preparing PDC with low stress levels.

Improving Stress Distribution: Samples prepared using this method exhibit residual compressive stresses that are uniformly distributed in both the axial and radial directions.

3. Increasing Tool Life

 Addressing Short Life Issues: Practical applications indicate that oversize residual stress results in shorter life performance for PDC. The alloy infiltration method directly resolves this key factor limiting lifespan by synthesizing high-quality PDC with low residual stress.

 Enhancing Wear Resistance and Structural Quality: PDC synthesized via this method possesses a high-density diamond layer structure. X-ray diffraction confirms the presence of cubic diamond, alloy, and carbide phases without any detected graphite phase. This promotes the growth of diamond-to-diamond (D-D) bonds, resulting in high-quality, wear-resisting tool materials.

The alloy infiltration method fundamentally reduces destructive residual stress through physical matching (reducing thermal expansion mismatch) and process optimization (precisely controlling binder proportions). This not only strengthens the material's microstructural bonding but also significantly extends the tool's service life.