This comes from the composites store website:
These high performance carbon shapes are produced by packing a high volume of carbon fiber into epoxy resin under tension resulting in an unmatched tensile and compression stength.
These shapes are twice the stiffness of Aluminum.
Compared to a wet lay-up of Carbon Tow the shapes are:
350% Stronger in Tension
550% Stronger in Compression
It doesn't explain why. Carbon Tow are long continuous strands of carbon fiber. So somehow putting it under tension first, then fixing it in position with the epoxy makes it stronger? How?