scispace - formally typeset
Search or ask a question
Author

Dongfang Zeng

Bio: Dongfang Zeng is an academic researcher from Southwest Jiaotong University. The author has contributed to research in topics: Hardness & Fretting. The author has an hindex of 11, co-authored 28 publications receiving 336 citations.

Papers
More filters
Journal ArticleDOI
TL;DR: In this paper, an improved wheel steel containing high contents of Si and Mn and a low content of Cr was developed for railway wheel steels, which is hardened by solid solution strengthening and refinement of pearlite interlamellar spacing.

56 citations

Journal ArticleDOI
TL;DR: In this paper, Austempered ductile irons (ADI) with three strength grades and one kind of wheel steel were matched with conventional rail steel and rolling-sliding wear tests were conducted.

47 citations

Journal ArticleDOI
TL;DR: In this paper, the microstructure and mechanical properties of ADIs such as tensile strength, yield strength, elongation and impact toughness were studied and the results showed that the strength of the three grades ADIs well satisfy the requirement of ASTM standard 897M-06 grade 900/650/09, grade 1050/750/07 and grade 1200/850/04.

43 citations

Journal ArticleDOI
15 Aug 2017-Wear
TL;DR: In this article, the authors studied the evolution of surface appearance and the initiation characteristics of fretting fatigue cracks in press-fitted specimens by interrupted rotating bending fatigue tests and found that the wear scar induced by fretting wear is a source for changes in each fretting damage zone boundary.

39 citations

Journal ArticleDOI
TL;DR: In this paper, a laser-dispersed treatment was used to improve the rolling contact wear and fatigue resistance of railway wheel steel by creating isolated glazed regions on the surface layer, which are composed of fine martensite and retained austenite.

39 citations


Cited by
More filters
Journal ArticleDOI
TL;DR: In this paper, a polydimethylsiloxane (PDMS) adhesive layer is deposited onto the cotton substrate, followed by the subsequent deposition of ZnO nanoparticles to enhance the surface roughness through an oil bath process.

147 citations

Journal ArticleDOI
TL;DR: In this paper, a superhydrophobic TiO 2 coating was fabricated on cotton fabric through a facile one-step hot-pressing process after being dipped in n-octyltriethoxysilane and Ti-containing precursor mixed solution.

101 citations

Journal ArticleDOI
TL;DR: In this article, the effect of various energy area densities on the distribution, size and mechanism of pores, slag inclusions and cracks in the DLD 24CrNiMo alloy deposition layer were investigated.
Abstract: 24CrNiMo alloy steel samples for preparing the brake disc of high-speed train were fabricated by direct laser deposition (DLD) with different laser energy area density (EAD). The effect of various energy area densities on the distribution, size and mechanism of pores, slag inclusions and cracks in the DLD 24CrNiMo alloy deposition layer were investigated. The results show that the increase of the EAD leads to the increase of the dilution index and area of the molten pool. The density of multilayer samples reached highest (99.25%) when the EAD was 100 J/mm2. The morphology of pores had irregular deformation when the EAD was low while had smooth sphere morphology when the EAD was high. The cracks ratio increased with the increase of the EAD while the content of inclusion defects decreased. A behavioural process for the re-melting of pore defects at different energy densities was discussed, and the formation of inclusion defects with low EAD was studied to illuminate the EAD effects on defects. The samples deposited at the 100 J/mm2 have no obvious defects and relatively high density, this EAD can be considered as a reference to prepare 24CrNiMo samples with low defects by DLD.

57 citations

Journal ArticleDOI
TL;DR: In this paper, an improved wheel steel containing high contents of Si and Mn and a low content of Cr was developed for railway wheel steels, which is hardened by solid solution strengthening and refinement of pearlite interlamellar spacing.

56 citations

Journal ArticleDOI
12 Jan 2018
TL;DR: In this article, the performance of Alloyed Ductile iron (ADI) was investigated using microscopy, coupled with analyzing software and a scanning electron microscopy to calculate the amount of retained austenite in the ausferrite matrix.
Abstract: Alloyed Ductile iron, austenitized at 840 °C for 30 min in a special sealed austempering furnace, was austempered for 30 min in molten salt mixture at 4 trial temperatures of 300 °C, 320 °C, 340 °C and 360 °C. Tensile strength, yield strength, percentage elongation and impact energy were evaluated for the as-cast and austempered samples. Microstructures were investigated using microscopy, coupled with analyzing software and a scanning electron microscopy. The specific wear of samples was tested using pin-on-disc wear testing machine. X-ray diffraction was performed to calculate the amount of retained austenite present in the ausferrite matrix. As-cast microstructure consists of ferrite and pearlite, whereas austempered ductile iron (ADI) contains a mixture of acicular ferrite and carbon enriched austenite, called “ausferrite”. Hardness and strength decreased, whereas ductility and impact strength improved with an increase in the austempering temperature. XRD analysis revealed that the increase in austempering temperature increased the retained austenite content. A decrease in wear resistance with austempering temperature was observed. Modified Quality Index (MQI) values were envisaged, incorporating tensile strength, elongation and wear resistance. MQI for samples austempered at 340 °C and 360 °C showed a better combination of properties. About an 8% reduction in energy consumption was gained when the heat treatment parameters were optimized.

55 citations