What is the strongest filament to use? I'm looking for a strong filament that can handle a large tension load and no bending deformation when a perpendicular force is applied to it. Any suggestions?
Carbon or glass fiber reinforced PLA likely has the strongest without deformation. PLA will snap before deforming.

Fiber reinforced ABS is also an option. ABS is stronger but will bend before breaking. 

Both are hard on nozzles and may require a stainless steel nozzle.