Is it permissible for the one being led in prayer (ma'mum) to carry the Mus'haf and read from it during a silent prayer or during the silent rak'ahs of a loud prayer, and would his prayer be invalidated if he were to do so?

If the worshipper (ma'mum) does not know how to recite Al-Fatihah well, he must read it from the Mushaf (copy of the Qur’an) because its recitation is obligatory. However, if he knows it well, he should not read from the Mushaf, because that distracts him from the Sunnah acts of prayer, and it was not transmitted from the Salaf (pious predecessors), and there is a difference of opinion regarding the validity of the prayer in such a case, even though the preponderant view is that it is valid. Reading from the Mushaf does not invalidate the prayer according to the majority of scholars, but Imam Abu Hanifa differed.