Despite their unique astrophysical relevance , the outcome of white dwarf binary mergers has so far only been studied for a very restricted number of systems . Here we present the results of a survey with more than two hundred simulations systematically scanning the white dwarf binary parameter space . We consider white dwarf masses ranging from 0.2 to 1.2 M _ { \odot } and account for their different chemical compositions . We find excellent agreement with the orbital evolution predicted by mass transfer stability analysis . Much of our effort in this paper is dedicated to determining which binary systems are prone to a thermonuclear explosion just prior to merger or at surface contact . We find that a large fraction of He-accreting binary systems explode : all dynamically unstable systems with accretor masses below 1.1 M _ { \odot } and donor masses above \sim 0.4 M _ { \odot } are found to trigger a helium detonation at surface contact . A substantial fraction of these systems could explode at earlier times via detonations induced by instabilities in the accretion stream , as we have demonstrated in our previous work . We do not find definitive evidence for an explosion prior to merger or at surface contact in any of the studied double carbon-oxygen systems . Although we can not exclude their occurrence if some helium is present , the available parameter space for a successful detonation in a white dwarf binary of pure carbon-oxygen composition is small . We demonstrate that a wide variety of dynamically unstable systems are viable type Ia candidates . The next decade thus holds enormous promise for the study of these events , in particular with the advent of wide-field synoptic surveys allowing a detailed characterization of their explosive properties .