I was writing a biography and my teacher (who is not an English teacher, he is a math teacher) made several marks on my paper for my use of "would". For example, I wrote,

"He would publish his first mathematical paper at the age of eighteen."

My teacher said I should have used published instead of would publish. He also said in class that since it is a biography that takes place in the past that this wasn't the correct use of past tense. I don't think he is right and I feel that this issue is more a stylistic difference. However, I am unsure as well so any help would be appreciated. I will put some more example below too. 

1. me-> "One year later he went on to earn his Ph.D..."\
him-> should have been earned and I should've got rid of went on to

2. me-> "He would be associated with the project until 1955."\
him-> should have been was and not would be

3. me-> "Von Neumann would go on to write, "[boring qoute]"\
him-> should have been went and not would go

4. me-> "Between 1927-1930 Von Neumann would teach Mathematics at University of Berlin."\
him-> should have been taught and not would teach