Thermal Stress Estimation of Tungsten Fiber Reinforced Titanium Composite by In-situ X-ray Diffraction Method

The tungsten fiber reinforced titanium composite (W/Ti) was produced by the spot welding method. This manufacturing method used only a simple spot welding system, and it did not need a vacuum chamber and a high temperature furnace such as existing common methods. The arranged tungsten fibers were held between titanium plates (thickness 0.5mm) and fixed by spot welding. Therefore, this W/Ti composite produced by spot welding did not join at all positions between the tungsten fiber and the titanium matrix because of the partial welding in the spot welding point. The coverage, a rate of welding area to the whole plate area, became 150% for the sample in this study, because it should make up for the partial welding by this method. From the microscopic observation in the cross section of the W/Ti composite, it was conformed the good jointing in the whole position between the tungsten fiber and the titanium matrix. On the other hand, the alteration of thermal residual stress under the thermal cycling was measured by the in-situ X-ray stress measurement technique. These results were discussed from the viewpoint of the thermal expansion coefficient mismatch between fiber and matrix.