The heat treatment process of titanium alloys is a key technology for regulating the microstructure and mechanical properties of titanium alloys through treatment methods such as solution treatment, aging, and annealing. Solution treatment involves heating the alloy below the phase transformation point and rapidly cooling it to obtain a supersaturated solid solution. Aging treatment promotes the precipitation of the second phase for strengthening. Double annealing can refine the grain structure and enhance the material's stability. Process parameters such as solution temperature (910-930℃) and aging temperature (520-560℃) directly affect tensile strength (up to over 1176MPa) and toughness. The domestic standard system has problems such as incomplete coverage and unsystematic process control. It is necessary to optimize parameter combinations and improve standards in combination with application scenarios.
In the research of Ti-6Al-4V titanium alloy, the solution temperature is selected within the range of 910 to 930℃ (40-100℃ below the phase transformation point of 970℃), and the aging temperature is controlled at 520-560℃ to achieve the best matching of strength and toughness. The 20-40mm thick plates are treated with a solution process at 910℃ and aging at 520℃, which increases the elongation by 15% while maintaining a tensile strength of over 1176MPa. The 920℃ solution treatment +560℃ aging solution increases the strength to the 1220MPa level, making it suitable for the manufacturing of high-strength components. The holding time should be adjusted according to the thickness of the material to ensure that the phase change is fully carried out.
After heat treatment, the specific strength of Ti-6Al-4V titanium alloy can reach 27-33, while maintaining good fracture toughness. An increase in solution temperature will intensify the β phase transformation, enhancing strength but reducing plasticity. Excessively high aging temperature will lead to over-aging softening. Through a combined process of multi-stage aging or deformation heat treatment, the regulation of grain boundary α phase and the optimization of dislocation density can be achieved, further expanding the service performance range of the material.
