Microstructure & Performance of Joints in High Temperature Alloys

Microstructure & Performance of Joints in

Superalloys www.msm.cam.ac.uk/phase-

trans

Shirzadi, Saindrenan & Wallach, 2003

Minimal gallium

Diffusion Bonding

Pure aluminium

Diffusion Bonding of Gallium -Treated Superalloy Surfaces

3-10 MPa pressure900-1250 oC1 h10-7 bar1 mg cm-2 gallium

Co-23Cr-10 Ni-7W0.2Ti-0.6C-0.5Zr wt%

100 µm

Shirzadi & Wallach

Ni-15Cr-10Co-9.5Mo4.2Al-3.6Ti-0.006B wt%

50 µm

Shirzadi & Wallach

Superalloy Cr Co Mo W Al Ti B C Si Zr Others

Inconel 718 18.3 0.1 2.85 0.5 0.92 0.003 0.02 0.08 0.01 0.08Mn, 0.0004SInconel 738 16 8.5 1.75 2.6 3.4 3.4 0.01 0.17 0.1 1.75Ta, 0.9Nb

C1023 15 10 8.5 4.2 3.6 0.006DSR142 8.3 13 1.5 6 3.4 7Ta, 1.8HfPWA647 23 Bal. 0 0 0.2 0 0.6 0 0.5 10Ni, 7W, 3.5 Ta

Directionally solidified nickel

superalloy

Single-crystal nickel superalloy

Shirzadi & Wallach

Shirzadi & WallachBonding completed in 1 hour

Kurz

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

Lowering Cr improves properties.

Polycrystalline coatings such as NiCrAlY.

Ni is anisotropic.

Single-Crystal Surface Engineering

E100 = 125 GPa E111 = 310 GPa

Sieborger et al.

Kurz

Dendrites grow along <100>.

Variant selected is closest to heat flux.

high aluminium MCrAlY

primary

low aluminium MCrAlY

primary

MCrAlY

CMSX-4

Transient liquid-phase bonding

Shirzadi & Wallach, 1999

Al-Li

TLP

TG-TLP

Shirzadi & Wallach, 1999

TG-TLP

Alloy 6082

Large gradient

Small gradient

Inertia Welding Process

No liquid phase

Can join dissimilar metals

Powder metallurgical alloy RR1000

Residual stressBaxter, Preuss, Withers

Rolls-Royce

Nottingham

Mechanically Alloyed

Oxide Dispersion Strengthened Metals

Fine dispersion of yttria particles

screw

shoulder

termination

2D Mixing Animation

Colegrove & Shercliff, 2002

Microstructure & Performance of Joints in

Superalloys www.msm.cam.ac.uk/phase-

trans