Distribution of temperature during fibre laser radiation and effects thereon phase transformation of ZrO2 engineering ceramic

Abstract

Distribution of surface and the bulk temperature was recorded during fibre laser surface treatment of ZrO2 engineering ceramic. The experimental readings were then compared with a finite element model which showed the flow and distribution of the laser induced heat as a result of the fibre laser surface treatment. Moreover, thermogravimetry–differential scanning calorimetry was used to collect data with respect to physical changes during heating and cooling of the ZrO2 engineering ceramic. The thermogravimetry–differential scanning calorimetry data and the finite element model predictions were then used to map the phase transitions within the ZrO2 engineering ceramic resulting from fibre laser surface treatment. The mapping revealed that the fibre laser surface treatment had generally resulted in a phase transformation of the ZrO2 engineering ceramic from the monoclinic (M) state to a mixture of tetragonal and cubic (T+C) followed by partially formed liquid (L) phase during fibre laser surface treatment and from L to T+C then T, followed by the M state during solidification.