Process Window and Material System Adaptability: The Realization Path of Pressureless Sintering

Pressureless sintering imposes extremely high requirements on the thermodynamic precise design of material systems. Under pressureless conditions, densification relies entirely on the volume of liquid phase formation, temperature window, and wetting behavior. Even minor compositional deviations can lead to sintering failure or degraded performance.

Studies show that under pressureless sintering at 875 °C for 60 min, the optimal addition levels are 7% for CuSn15 liquid phase and 10% for Fe Powder. Deviations from this ratio result in significant reductions in relative density and bending strength. This confirms that successful pressureless sintering depends on precise matching ofcomposition‑temperature‑time, with an extremely narrow process window.

Pressureless sintering is particularly suitable for well‑designed pre‑alloyed powder systems. Compared with elemental mixed powders of the same composition, pre‑alloyed powders achieve a 5% higher relative density and an HRB 7 increase in hardness after vacuum pressureless sintering at 860 °C, demonstrating strong adaptability to pre‑Alloyed Materials.

Moreover, pressureless sintering offers unique advantages in producing complex‑shaped, thin‑walled, or ultra‑long components such as diamond saw beads. It avoids geometric limitations imposed by hot‑pressing molds, making it irreplaceable in certain specialized fields.

In summary, pressureless sintering pursues the upper limit of performance through precision material design.