As a general rule, AmeriCorps members may obtain a deferment of payments on the principal of any federally guaranteed student loan for the length of their service. The terms and conditions of available deferments differ depending on the type of loan, the date the loan was dispersed, and the policies of the individual loan holder. Some older federal student loan programs allow AmeriCorps members a categorical deferment, while newer federal loan programs may require that you apply for an "economic hardship" deferment. Please note that your loan holder, not CNCS grants you student loan deferments.
See also:
How do I place my qualified loan in deferment?
What is the difference between ”forbearance” and ”deferment”?