What grade of aluminum is not bendable？

Most grades of aluminum are bendable to some extent due to their inherent ductility. However, certain aluminum alloys with high strength and hardness, such as those in the 7000 series (e.g., 7075), are less malleable and more prone to cracking when bent compared to softer alloys like those in the 1000, 3000, or 5000 series.

Alloys like 7075 are typically used in applications where high strength and durability are required, such as aerospace components and structural parts. While they can be formed and shaped through processes like forging and machining, they are less suitable for bending operations compared to softer aluminum alloys.