Toyota Motor Corp. is set to become the next global automaker to begin making the expensive shift from steel to aluminum for a high-volume vehicle.

The U.S.-built Camry, the country's best-selling car, is slated to get an aluminum hood in 2018, according to a source familiar with the plans.

Toyota's first foray into aluminum closures in North America will come next year when the 2016 Lexus RX 350 crossover, which is made in Cambridge, Ontario, gets an aluminum hood and liftgate, the source said.

The aluminum sheet for the Camry hood likely will come from a joint venture between Toyota Tsusho Corp., a trading company affiliated with Toyota Motor Corp., and Kobe Steel to produce more aluminum sheet metal in the U.S. Toyota will be among the venture's first customers, several sources confirmed. Production is expected to begin in 2017 and ramp up to full output at the beginning of 2018.

Negotiations on site selection and some details for the joint venture are expected to conclude this month. The operation, which will produce 100,000 tons of aluminum sheet capacity annually, will be built in the Southeast, possibly near Wise Alloys, a Muscle Shoals, Ala., aluminum producer for the food and beverage industries, which will source the master coils to make the aluminum sheet, according to a source involved with negotiations.

Toyota declined to comment on specific plans for the Camry but said it plans to use more aluminum across its lineup.

"Toyota has plans to use aluminum on future vehicles for hood, closures and parts for lightweighting," said spokeswoman Jana Hartline. "Also, we will increase usage of mix metals and resin materials to enhance lightweighting efforts."

Toyota uses aluminum in the hood and trunk of certain vehicles made in Japan, including the Prius, as well as the hoods of most Lexus sedans and the Scion FR-S sports car. Neither the 2014 Camry nor the heavily re-engineered 2015 Camry uses aluminum for its frame or body panels.

Monte Kaehr, chief engineer for the 2015 Camry in Ann Arbor, Mich., declined to comment when asked whether Toyota plans to use aluminum to cut weight on the next-generation Camry.

"It's no secret that the entire industry is aggressively pursuing aluminum," Kaehr said.

Ford Motor Co. has begun a major retooling of its Dearborn truck plant to produce the F-150 pickup with aluminum body panels. The F series is the best-selling vehicle in the U.S.

Ford said in January at the Detroit auto show that it would begin making the truck with aluminum body panels instead of steel. The move will shave up to 700 pounds from the truck.

The 2015 F-150 goes on sale this year.

A retooling of the Camry, which sold more than 300,000 units through the first eight months of the year, could face aluminum supply constraints in the United States, so Toyota -- and other automakers -- will need a local infrastructure to handle the volume of vehicles scheduled for production.

"We envisage that in addition to Japanese car companies, the joint venture would market the aluminum sheet to North American, European and other automobile manufacturers based in North America," said Gary Tsuchida, a spokesman for Kobe Steel in Tokyo.

Through the joint venture, Kobe Steel is responsible for production, quality assurance and business operations, while Toyota Tsusho will market the products, according to a press release from Kobe Steel.

Toyota's venture into aluminum shows that the trend toward lightweighting to meet corporate average fuel economy regulations isn't limited to heavier trucks and SUVs, said Andrew Lane, a metals analyst with Morningstar.

"Although high-performance sports cars have historically used aluminum across hoods and body panels, the Camry would constitute the first sedan produced on a large-scale basis to switch to aluminum," Lane said.

The Camry has been the best-selling car in America for past 12 years, with sales this year through August up 7 percent from a year earlier.

A shift toward aluminum "ultimately makes sense, given that CAFE regulations apply across an entire fleet and the Camry comprises such a large portion of Toyota's fleet, meaning that the impact to fleetwide fuel efficiency will be substantial," Lane said.

Other automakers have been relying more on aluminum for vehicle hoods and body panels. All General Motors full-size pickups and SUVs have aluminum hoods, as do 80 percent of Chrysler Group vehicles. Niche automakers also are adding more aluminum to their frames. Jaguar Land Rover's Jaguar XE and XJ sedans, XK and F-Type coupes and convertibles and Range Rover have all-aluminum bodies and structures for 2015.

"We will likely continue to see more high-volume models switch from steel to aluminum in the years to come, while lower-volume models remain steel-intensive," Lane said. "Many automakers, however, are still likely waiting to see how the F-150 rollout proceeds before further exploring the use of aluminum."