Alcoa Inc. cleared a final hurdle in its $1.5 billion takeover of RTI International Metals, a Moon-based titanium manufacturer that is expected to help the aluminum giant win more business from the aerospace industry.

RTI shareholders this week voted to approve the all-stock deal, which gives them 2.8315 Alcoa shares for each RTI share. Alcoa expects to close the transaction Thursday.

“We look forward to taking our innovative technologies to the next level as part of Alcoa's ongoing transformation as a lightweight, multi-material innovator,” RTI CEO Dawne Hickton said in a written statement.

Alcoa announced the deal in March, calling the acquisition of RTI “a major milestone” in its transformation into a manufacturer of high-value metal components for the aerospace industry, which is trying to reduce weight to save fuel. With RTI, Alcoa gains a larger footprint in the titanium industry, which is the world's fastest-growing aerospace metal.

Sales to the aerospace and defense industries accounted for 80 percent of RTI's $794 million in revenue last year. Growing use of titanium in aircraft is predicted to increase RTI's revenue to $1.2 billion by 2019, Alcoa has said.

Alcoa shares closed Wednesday down 24 cents, or 2 percent, to $9.99.

“Innovation and scale are critical to winning in both the titanium and aerospace industries,” Hickton said. “(The) vote shows our shareholders understand that RTI and Alcoa are a natural strategic fit and that, together, we will be better positioned to compete in the global marketplace and to maximize shareholder value.”