|
|
|
| Diffusional homogenization treatment of Ni - Cr - Mo - Cu corrosion resistance alloy and evolutions of its microstructure and properties |
| State Key Laboratory. of Gansu Advanced Non-ferrous Metal Materials, Lanzhou University of Technology, Lanzhou, Gansu 730050, China |
|
|
|
|
Abstract Using three-dimensional diffusion theory, the homogenization treatment of newly-developed as-cast Ni - Cr - Mo - Cu alloys and evolutions of its microstructure and properties were studied. The results showed that the coarser as-cast microstructures from three melting methods, hand-arc furnace（fine cellular structures about 20 μm cell size）, vacuum induction furnace （coarse dendritic structures about 80 100 μm spacing）and consumable electrode vacuum arc furnace（ well-developed directional dendrites about 60 - 80 μm spacing） , all disappeared and segregated mierostruetures were homogenized after solution treatment at 1 140 - 1 170 ℃ for 2.5 h. Compared with the as-cast alloys, the corrosion resistance of the as-solution alloys in four kinds of typical corrosive agents was improved （ above 15% - 25% ）. Both hardness and strength were increased by about 30%. The present Ni - Cr - Mo - Cu alloy has excellent corrosion resistant ability, especially in FeCl3 and HCl solutions, about 2 - 3 orders as high as 1Cr18Ni9Ti. Through analysis of the Fourier series solution for diffusion equation, the semi-experiential formula of solution treating time was derived for the as-cast Ni - Cr - Mo - Cu alloys.
|
|
|
|
|
|
|
|
|
2009, Vol. 30 
