President Trump touted the strong relationship between the USA and Australia as the countries celebrate 100 years of working together since World War I.
In December, Trump issued an executive order urging the private sector to increase exploration of critical minerals to reduce dependence on imports, improve national security, and enhance the technological superiority and readiness of United States armed forces.
Asked if he still supported Mr Joyce as deputy prime minister, Mr Turnbull said: "These are matters for the leadership of the National Party".
He blamed the "poor leadership" of previous United States administrations for the trade imbalance.
Mr Turnbull and his wife Lucy departed the U.S. for Canberra on Saturday (Sunday morning AEDT). "We're going to get rid of the bump stocks and we're going to do certain other things".
"The Trans-Pacific Partnership was not a good deal for us", Trump said, stressing that he would rejoin a deal that was better for the United States, but prefers bilateral deals over pacts involving many countries.
Turnbull said the meeting will help generate jobs for both sides.
The "mateship" - as the Australians have termed the longstanding alliance with the United States - was strained in the early days of the Trump presidency, with the US leader critical of a program to accept refugees turned away from Australia. U.S. President Donald Trump on Friday met with visiting Australian Prime Minister Malcolm Turnbull here on closer economic and security relations between the two countries.
A spokesman for Mr Turnbull said the Australian Federal Police advised the crash had "no impact on the prime minister". "Here, we're working very hard to do the same".
"You have an amendment to your Constitution which deals with gun ownership".
"This has been a very, very valuable visit", Mr Turnbull told reporters on Saturday before leaving for Maryland's Andrews Air Force Base and the long flight home.
"We believe we have made a very compelling case, but obviously the administration has to finalise its decision in this area", Mr Turnbull said. "But I think we're well on the way to solving that terrible problem that happens far too often in the United States". Trump called Australia "a great country", and Turnbull noted this year marks "100 years of mateship" between the two countries and predicted 100 more years of friendship to come.
The large presence of Australian leaders led the association's chairman, Nevada Governor Brian Sandoval, to joke: "We wondered who's running government in Australia right now?"