860 °C solution treatment optimizes aging response in Ti–5Cu alloy

Solution treatment at 860 °C for 1,800 s produced the best overall mechanical properties among the conditions tested for Ti–5Cu alloy sheets, according to a materials study examining phase dissolution, recrystallization and aging strengthening. The treatment yielded an ultimate tensile strength of 995 ± 4 MPa, a yield strength of 909 ± 2 MPa and an elongation after fracture of 9.4%. Researchers investigated solution temperatures from 780 to 900 °C and holding times from 20 to 3,000 s, then assessed how the resulting microstructures responded to aging.

The study identifies Ti₂Cu as the primary intermediate phase in the alloy. At a constant solution temperature, the aging strength initially increased rapidly as solution-treatment time increased, then gradually stabilized and declined slightly at prolonged holding times. The researchers developed a quasi-steady-state solute-diffusion kinetic model based on the geometric characteristics of the intermediate phase to estimate Ti₂Cu dissolution.

Calculated dissolution times for Ti₂Cu particles with radii of 0.1–0.5 μm at 860 °C agreed well with the experimentally observed hardness evolution and mechanical-property results. Microstructural observations showed that recrystallization at 860 °C was essentially complete within approximately 600 s, when the average grain size was about 3.96 μm. Extending the solution treatment beyond this period was associated with accelerated grain-boundary migration and weakened boundary pinning, followed by rapid grain coarsening.

The study links these observations with the way solution-treatment duration changes the alloy’s structure before aging, while avoiding a simple relationship in which longer treatment always produces stronger material. Analysis of aging precipitation showed that higher solution temperatures significantly promoted precipitation during aging, whereas solution-treatment time had a relatively limited influence on precipitation morphology. In other words, temperature and duration affected distinct parts of the observed response: the aging analysis emphasized temperature’s association with precipitation, while the microstructural analysis documented substantial changes in recrystallization and grain size as treatment time increased.

The phase-dissolution model supplied an additional comparison between estimated Ti₂Cu dissolution times and measured hardness and mechanical-property changes. These findings are specific to the investigated Ti–5Cu alloy sheets, experimental conditions and ranges of 780–900 °C and 20–3,000 s. They do not establish that the same optimum or mechanism applies to other titanium-copper compositions or processing routes.

Subject of Research: Effects of solution-treatment temperature and duration on Ti₂Cu dissolution, recrystallization and aging strengthening in Ti–5Cu alloy sheets.

Article Title: Phase dissolution during solution treatment and its effect on aging strengthening in Ti–5Cu alloy

Article References: Wang, W., He, Y., & Yue, X. (2026). Phase dissolution during solution treatment and its effect on aging strengthening in Ti–5Cu alloy. Journal of Materials Science, 61(41), 31984-32002. https://doi.org/10.1007/s10853-026-13648-1

Image Credits: AI Generated

DOI: 10.1007/s10853-026-13648-1

Keywords: Ti–5Cu alloy, Ti₂Cu dissolution, solution treatment, aging strengthening, recrystallization, grain coarsening, solute diffusion, tensile strength, precipitation, materials processing, Phase, dissolution