Microstructure Performance of Joints in High Temperature Alloys

Microstructure & Performance of Joints in High Temperature Alloys

Microstructure & Performance of Joints in Superalloys www. msm. cam. ac. uk/phase-trans

Diffusion Bonding Pure aluminium Minimal gallium Shirzadi, Saindrenan & Wallach, 2003

Diffusion Bonding of Gallium Treated Superalloy Surfaces 3 -10 MPa pressure 900 -1250 o. C 1 h 10 -7 bar 1 mg cm-2 gallium

100 µm Co-23 Cr-10 Ni-7 W 0. 2 Ti-0. 6 C-0. 5 Zr wt% Shirzadi & Wallach

50 µm Ni-15 Cr-10 Co-9. 5 Mo 4. 2 Al-3. 6 Ti-0. 006 B wt% Shirzadi & Wallach

Directionally solidified nickel superalloy Single-crystal nickel superalloy Shirzadi & Wallach

Bonding completed in 1 hour Shirzadi & Wallach

Single-Crystal Repair Melt shallow layer of SX substrate using laser. Feed melt pool with alloy powder. Epitaxial columnar growth. Repeat to build thicker layers. Kurz

Single-Crystal Repair Kurz

Kurz

Single-Crystal Surface Engineering Lowering Cr improves properties. Polycrystalline coatings such as Ni. Cr. Al. Y. Ni is anisotropic.

Sieborger et al. E 100 = 125 GPa E 111 = 310 GPa

Dendrites grow along <100>. Variant selected is closest to heat flux. Kurz

high aluminium MCr. Al. Y primary b low aluminium MCr. Al. Y primary g

MCr. Al. Y CMSX-4

Transient liquid-phase bonding

Al-Li TLP TG-TLP Shirzadi & Wallach, 1999

TG-TLP Alloy 6082 Large gradient Small gradient Shirzadi & Wallach, 1999

Inertia Welding Process No liquid phase Can join dissimilar metals Powder metallurgical alloy RR 1000 Residual stress Baxter, Preuss, Withers

Rolls-Royce Nottingham

Mechanically Alloyed Oxide Dispersion Strengthened Metals

Fine dispersion of yttria particles

screw shoulder termination

2 D Mixing Animation Colegrove & Shercliff, 2002

Microstructure & Performance of Joints in Superalloys www. msm. cam. ac. uk/phase-trans