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发表时间：2022-10-10

发表刊物：中国激光

所属单位：机械工程学院

卷号：41

期号：7

页面范围：0703012

ISSN号：0258-7025

摘要：Thermal stress caused by oversized temperature gradient in the process
   of laser cladding ceramic coating on metal substrate usually makes the
   coating cracked.Reducing the temperature gradient of the laser cladding
   process can reduce the thermal stress to a certain degree to suppress
   the generation of cracks.Through numerical simulation of temperature
   distribution during laser cladding Al_2O_3 coating on Ti6Al4V
   substrate,a method of providing preheating and slow-cooling using top
   hat laser beam is proposed.Temperature distribution and temperature
   gradient of the coating with preheating and slow-cooling are discussed
   by changing the spot size and power density of the top hat assistant
   laser beam.The results show that there is a significant feature of
   preheating and slow-cooling during the cladding process,the top hat
   assistant laser beam can reduce the temperature gradient effectively.The
   temperature gradient of the plastic point(1533 K)of Al_2O_3reduces while
   the preheating and slow-cooling temperature raises.But the temperature
   gradient of the plastic point will rebound when the preheating and
   slow-cooling temperature is near the plastic point.Higher preheating and
   slow-cooling temperature make the cladding process better,but
   temperature around the plastic point should be avoided.

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