Typically your legal personal representative will act as trustee of the fund.  Section 17A (3) Superannuation Industry Supervision Act 1993 (SISA).  In most cases they will have discretion as to how your balance will be distributed.

Your superannuation benefit does not form part of your estate so your Will, should you have one will not be able to control the distribution of your superannuation balance.

If you wish to have control over how your superannuation balance is to be distributed upon your death, then a Binding Death Benefit Nomination (BDBN) should be executed, as this 'binds? the trustee of your SMSF to distribute your balance in accordance with your wishes and gives them little discretion.  Section 59 (1A) SISA 1993 and Regulation 6.17A Superannuation Industry Supervision Regulations 1994 (SISR).

Refer - http://mcnamaraandco.com/news/2012/09/what-is-a-death-benefit-nomination-dbn/