1972: Black Sabbath vol. 4. I'm 2 years old at this point, so the significance of that album eludes me for some time.
1980: Iron Maiden releases their first album, and Discharge release their first EP. Other bands probably did stuff that year as well, but who cares? (OK, British Steel is worth a mention, as is Van Halen's Women and Children First, and I do believe Motörhead had a good year as well...).
1982: I officially get into metal after hearing Number of the Beast on my friend's walkman at a school athletic event. Discharge release 'Hear Nothing See Nothing Say Nothing', and Mercyful Fate release their self-titled debut. Dio rehearses material for 'Holy Diver', Metallica rehearses for 'Kill 'em All', Slayer rehearses for 'Show No Mercy'. On a sad note, Randy Rhoads dies.
1985: I go to my first metal concert - Iron Maiden, with Accept opening. I'm changed forever. No essential releases that I can think of that year, aside from Live After Death and Corrosion of Conformity's 'Animosity'. And Slayer's 'Hell Awaits'. Voivod's 'War and Pain' turns 1 year old.
1986: I join my first band. 17 years later, I've yet to make an impact on the world of music. Slayer releases Reign in Blood, and Voivod records Killing Technology. 'Master of Puppets' is released, and though a great album, it's not as good as RTL, and therefore is the beginning of Metallica's slide into shittiness.