2098 is a third-generation aluminum-lithium alloy, developed alongside grades like 2050 and 2099 to close the fracture toughness and corrosion resistance gaps that limited first-generation Al-Li alloys such as 2090. It carries 3.20-3.80% copper for age-hardening strength and 0.80-1.30% lithium for the density and stiffness benefits that define this family: each percent of lithium added by weight reduces density by roughly 3% and increases elastic modulus by roughly 6% compared with conventional aluminum. Controlled magnesium, manganese, and zinc additions round out the aging response without pushing the alloy back toward the anisotropic, delamination-prone behavior of early Al-Li grades.

As a modern, refined Al-Li alloy, 2098 is aimed at commercial and military aircraft structures where a favorable strength-to-weight ratio and improved damage tolerance matter more than raw cost. It's typically supplied as certified sheet or plate for qualified aerospace fuselage and structural applications, and like the rest of this family it is normally machined in relatively thin, close-tolerance sections rather than heavy general-purpose stock.

2098 machines with the cutting-force and chip-formation behavior typical of aluminum, but its lithium content makes it more reactive at the tool-workpiece interface than conventional 2xxx grades. That reactivity raises the risk of built-up edge if the insert isn't sharp or the speed is set too conservatively, so a polished, positive-rake edge and a coating suited to non-ferrous work help maintain a clean surface finish. Consistent coolant or lubrication is worth the extra attention, both to manage the lithium's reactivity and to keep heat away from the cutting zone.

Chip control deserves the same deliberate approach used across this whole alloy family: aluminum forms long, continuous chips, so chipbreaker geometry and feed rate need to be set up to break them cleanly. Because 2098 is normally machined in thin aerospace sheet and plate sections, keeping cutting force and localized heat under control is important for holding tight dimensional tolerances and avoiding distortion in the finished part.

Even with the added care lithium requires, 2098 still runs at speeds well above steel or titanium thanks to aluminum's low shear strength and high thermal conductivity. A sharp, well-prepared edge run at the recommended speed produces better results than a slower, more hesitant pass.