Investigation on the microstructure and creep behavior of laser remelted thermal barrier coating

SURFACE & COATINGS TECHNOLOGY

卷:369

Article

de Freitas, Filipe Estevao¹  Briguente, Flavio Perpetuo²  dos Reis, Adriano Goncalves³  de Vasconcelos, Getulio⁴  Pereira Reis, Danieli Aparecida^1,2 

[1] Univ Fed Sao Paulo, ICT, UNIFESP, Sao Paulo, Brazil

[2] ITA, DCTA, Sao Jose Dos Campos, Brazil

[3] Univ Estadual Paulista Unesp, Inst Ciencia & Tecnol, Sao Jose Dos Campos, SP, Brazil

[4] Inst Estudos Avancados, Foton IEAv, Sao Paulo, SP, Brazil

关键词: Laser remelting;    Thermal barrier coating;    Creep;    Titanium alloys;   

DOI  :  10.1016/j.surfcoat.2019.04.068

来源: Elsevier

【 摘 要 】

Laser surface modification of the thermal barrier coating was investigated with the aim of increasing creep resistance. Yttria-stabilized-zirconia (YSZ) with a CoNiCrAlY bond coat was deposited by air plasma spraying on equiaxed Ti-6Al-4V substrates. Analysis was carried out comparing uncoated samples with as-sprayed and laser remelted ones. A cross section and detailed characterization of coating surface was carried out by scanning electron microscopy and X-ray diffraction techniques. Mechanical properties in terms of microhardness and creep resistance were evaluated. Constant load creep tests were conducted at stress levels of 125 to 319 MPa at 500 degrees C and 600 degrees C. A dense ceramic layer of thickness about 40 mu m was formed by laser remelted treatment and its microhardness surface was higher than the other layers. As-sprayed YSZ had higher creep resistance than other samples. Analysis of creep behavior showed that the steady-state creep rate of laser remelted samples had about 42% reduction in 600 degrees C condition, evidencing a higher creep resistance than uncoated material. SEM images revealed a ductile fracture with presence of equiaxed dimples.

【 授权许可】

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