Bionic Repair of Thermal Fatigue Cracks in Ductile Iron by Laser Melting with Different Laser Parameters

Abstract

Nodular iron brake discs typically fail due to serious thermal fatigue cracking, and the presence of graphite complicates the repair of crack defects in ductile iron. This study presents a novel method for remanufacturing ductile iron brake discs based on coupled bionics to repair thermal fatigue cracks discontinuously using bio-inspired crack blocking units fabricated by laser remelting at various laser energy inputs. Then, the ultimate tensile force and thermal fatigue crack resistance of the obtained units were tested. The microhardness, microstructure, and phases of the units were characterized using a digital microhardness meter, optical microscopy, scanning electron microscopy, and X-ray diffraction. It was found that the units without defects positively impacted both the thermal fatigue resistance and tensile strength. The unit fabricated at a laser energy of 165.6 − 15 + 19 J/ mm 2 had sufficient depth to fully close the crack, and exhibited superior anti-cracking and tensile properties. When the unit distance is 3 mm, the sample has excellent thermal fatigue resistance. In addition, the anti-crack mechanism of the units was analysed.

Effects of angle formation between melted zone and friction direction on thermal fatigue and wear resistance of truck drum brake

“…As shown in Figure 13, there are a large number of wear debris in the crack, and the furrow through the crack is obviously deeper. Because the bionic coupling unit has good supporting function, 29 as well as hindering effect and dispersing effect, 30 the overall wear resistance of the bionic samples is better than that of the blank sample. However, due to the different angles of the bionic coupling single model, the impeding effect on the thermal fatigue crack is different, resulting in the number of cracks, and length of the crack is different, which directly leads to the difference in the weight loss and wear performance of the different angle models.…”

Advances in Laser Materials Processing

“…Laser surface treatment to repair surface defects and cracks in irons, steels, and composites [13][14][15][16]; 3.…”

Study on Antifatigue Crack Growth Characteristics of Ball-End Milling Bionic Surface

“…Fatigue resistance of steel surface. Inspired by bionics, Ma et al [7,8] proposed a discontinuous laser melting crack repair method to repair the thermal fatigue cracks of the brake disk, thereby prolonging the service life of the brake disc and increasing repair efficiency of brake disks. Keith et al [9] studied the fatigue life of thermally induced cracks in H13 tool steel.…”