Alcoa has recently announced an investment of $22 million in a new Hot Isostatic Pressing (HIP) facility located in Muskegon County, Michigan. With the HIP process, the facility will use elevated temperatures and extreme pressures to press powdered products into fully dense, high strength parts.
Powder metallurgy has been around for a long time, but 3D printing is relatively new in this field and this is where HIP technology could be a real breakthrough. HIP allows 3D-printed nickel-based superalloy hot section components to be printed and then densified into a form solid, durable and tough enough to be reliably used in jet engines.
HIP utilizes enormous pressures with 7,000 PSI as an approximate baseline. 15,000 PSI is common, but for difficult to sinter materials, pressures on the order of 40,000 PSI may be required.
In contrast, temperatures are not as high as you might imagine. For aluminum it could be as low as 900 degrees Fahrenheit. Even for superalloys, 2000 degrees Fahrenheit or so might be a typical process temperature. These temperatures are below the melting point of the material. HIP is not a melting process, but actually a combination of elevated temperature and extremely high pressures causing a complex diffusion process between the grains.
It’s complex, but it’s proven to work with powder metallurgy and in the ceramics industry it’s a known quantity. The ability to combine isostatic pressing with 3D printing and superalloy materials may open a new world of low cost, net-shape or near net-shape engine parts.
Alcoa is looking at surging commercial aircraft orders and a massive order backlog at Boeing and Airbus. They need highly efficient, next-generation turbofan engines, which use complex, multi-stage hot section designs. HIP may be the answer to low cost, high performance hot section needs.
Alcoa Power and Propulsion expects a nine to 10 percent growth rate in this market throughout 2015 and expects to make $2.2 billion in revenue.
To learn more about Alcoa and hot isostatic pressing, visit alcoa.com.
Hot Isostatic Pressing Process b-roll courtesy Erasteel