No, units lose all their attributes when you throw them into an army. Once in the army, they only lend their health bar to the army, and engage in combat as they normally would. Armies also claim a maximum movement per turn of one more move than the slowest unit in the army. So, if you have a Knight, an Medieval Infantry, and a Calvalry in one army, your army is going to move 2 squares each turn, because the slowest unit in it is a Medieval Infantry, which only moves 1 per turn. 1+1=2.