The effect of microstructure on mechanical properties in inertia welded titanium 6-4

Yates, Adam (2015). The effect of microstructure on mechanical properties in inertia welded titanium 6-4. University of Birmingham. M.Res.

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Abstract

The inertia welding (IW) of Ti64 was examined in terms of the microstructure and mechanical properties. The microstructure from two smalls scale inertia welded rings was observed using SEM. These microstructures were assessed in both the Hoop and Radial directions. Mechanical testing including micro-hardness, mechanical threshold and crack propagation testing, fracture toughness, tensile testing and low cycle testing was evaluated. The results show that the microstructures of both IW and LFW Ti64 are very similar with various weld zones being observed. The micro-hardness is far superior in the weld zone to that of the parent material. The most significant controlling parameter of the microstructure is the cooling rate.
The Tensile properties of both IW and LFW Ti64 are superior to that of the parent and failure will not occur within the weld, although the LCF behaviour was not as favourable in IW. Crack growth rate is slower in the hoop direction than radial direction although this trend is reversed at increased temperature due to a switch from transgranular to intergranular crack growth.
This work suggests that IW of Ti64 shows promise, although further work is required on larger scale welds before the manufacture of fan disks made from IW Ti64 can be substantiated.

Type of Work:

Thesis (Masters by Research > M.Res.)

Award Type:

Masters by Research > M.Res.

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