Discussion You've measured fracture toughness of 6061-T3 at two thicknesses namely 3 mm and 6 mm. You need to plot K vs B. On this plot you need to include other values of Kc found in the literature. - You need to discuss the trend of the graph, i.e. Kc should reduce as B increases why is this, what is happening. You might be able to support your findings by observation of the fracture surfaces. Your literature review might also identify how grain orientation affects KC, why is this and what are the mechanisms involved.