One of the techniques he mastered in these 7 months was an absolute defense technique that would greatly reinforce the heavenly armor technique that Zhang Yi already had, this was the Divine tortoise shield technique: a technique that can withstand any attack within 3 times the defense of the user in the time that qi endures.
So he would have 6 times the normal defense when using the dragon scales and the celestial armor technique if he used the divine tortoise shield technique he could defend against attacks of up to 18 times the defense of Zhang Yi, while his qi endured.
Zhang Yi could not imagine an enemy that could have an attack that exceeded 18 times his defense if there was someone like that he would be dead anyway, maybe his master had such an attack.