Brazil took in a "mere" 106K, but 1.5M moved to Argentina.
Huh? I'm not sure where you're 1.5 million getting that figure from, but I only see 302,800 Italians emigrating to Argentina in the 1946-1960 period and 455,000 going to Canada and the United States, with the largest portion going to Canada (which had signed a bilateral with Italy in 1950 allowing large scale immigration) during the same period. Below is a link.
http://cronologia.leonardo.it/emidove.htm