Influences of Laser Condition and Slit Shape on Joinability of Zircaloy‐SiC/SiC Composite Tube Joint

Experimental studies on joinability of zircaloy and SiC/SiC composite with titanium powder

“…The rotational speed and laser irradiation time for the prevention of titanium powder dispersion were 60 rpm and 1.2 sec, respectively, while those for the slits were 60 rpm and 3.2 s respectively. Those laser irradiation conditions were decided according to our previous studies . Although the smoke was not observed apparently during the laser irradiations to the slits and the mechanical calking joint of Zircaloy and SiC/SiC composite tubes was successfully produced, the air leak test of this calking joint indicated that this joint is still insufficient for the endcaps of SiC/SiC composite cladding.…”

“…A 500 W diode laser, which was employed in our previous studies, is used for the laser cladding, and the shape of beam spot at a focal position is a rectangle whose size is 2600 × 300 μm 2 , so that the wide width laser irradiation may enhance the debonding between Zircaloy and SiC/SiC composite tubes. Then, in this research, a 500 W fiber laser was employed instead of the diode laser where the shape of fiber laser beam spot at a focal position was a circle whose diameter was 200 μm.…”

“…Based on our previous studies, a flat cuttings were conducted for the inner surface of Zircaloy and the outer surface of SiC/SiC composite as shown in Figure . Where thickness of Zircaloy and SiC/SiC composite tubes was reduced to be about 0.35 and 0.85 mm, respectively.…”

“…However, the airtightness was still insufficient for the endcap seal of SiC/SiC composite tube because all the proportional solid solution was not uniformly generated along circumferential direction. Moreover, the examinations about the 500 W diode laser irradiation and the insert method of titanium micro‐powder suggest that the wide width laser irradiation seems to be inadequate because the larger shrinkage of Zircaloy would enhance the debonding between two tubes and the hook slit is considered to be the best cutting method for holding the titanium powder during the laser irradiation …”

“…Moreover, the examinations about the 500 W diode laser irradiation and the insert method of titanium micro-powder suggest that the wide width laser irradiation seems to be inadequate because the larger shrinkage of Zircaloy would enhance the debonding between two tubes and the hook slit is considered to be the best cutting method for holding the titanium powder during the laser irradiation. 18 In this research, three types of hook silt were employed for packing titanium micro-powder and the influence of titanium powder packing method on joinability between Zircaloy and SiC/SiC composite tubes were examined, where 500 W fiber laser was used instead of diode laser in order to prevent the effect of wide width laser irradiation.…”