The Thermal Fatigue Resistance Of Bionic Vermicular Cast Iron Processed By Laser And Its Influence On The Wear Resistance

The laser has characteristic of energy concentration. Using this characteristic, thebio-mimetic units, which have smaller size and better characteristics, are processed onthe surface of vermicular graphite cast iron. The vermicular graphite cast iron surfacecoupled with the bionic units, which mimic the non-smooth and coupling structure oforganisms table, can significantly improve its wear-resistance and thermal fatigueresistance. The studies focus on the influence of thermal fatigue parameters onbio-mimetic samples’ thermal fatigue resistance, the influence of thermal fatigueparameters on bio-mimetic samples’ wear resistance and the relationship between thethermal fatigue resistance and wear resistance.The application of vermicular graphite cast iron brake disc shows that, in mostcases, the brake disc is subjected to the wear behavior which is after different degreesof thermal fatigue. Therefore, the failure of the brake disc is a together result ofthermal fatigue and wear. So the thermal fatigue resistance and the wear resistancewhich is after different degrees of thermal fatigue of the vermicular graphite cast ironprocessed by laser bionic treatment are studied. The experimental results show thatwith the deepening of the degree of thermal fatigue (thermal fatigue cycles increasedor thermal fatigue temperature increased), the thermal cracks numbers and the longestcrack length of samples increase, that is to say the thermal fatigue resistance ofsamples degrades. But under the same degree of thermal fatigue, the cracks numberand the longest crack length of the bio-mimetic samples are lower than those of theuntreated samples; this indicates that the thermal fatigue resistance of bio-mimeticsamples is superior to the untreated samples. Meanwhile with thermal fatigue cyclesor thermal fatigue temperature increasing, the abrasion loss of samples increase, andthe wear resistance of samples decreased. While the abrasion loss of bio-mimeticsamples is always lower than that of untreated samples, this result indicates that evenafter the thermal fatigue, the laser bio-mimetic process is still an effective way to improve the wear resistance of vermicular graphite cast iron.