The poor wear resistance of 316L stainless steel restricts further practical application. In this study, to improve its microhardness and wear resistance, the TiC and NbC ceramic particles were introduced to 316L powder fabricate (Ti, Nb)C ceramics-reinforced composite coatings by laser cladding. The effects of ceramics addition on the phase composition, microstructure, microhardness, and wear properties of the composite coating were investigated with an X-ray diffractometer, optical microscopy, scanning electron microscopy, a Vickers hardness tester, and a multi-functional surface performance tester. Results indicate that the TiC and NbC ceramic particles were distributed at the grain boundaries, effectively inhibiting the grain growth and refining the microstructure. The addition of ceramic particles could have decreased the temperature gradient and promoted the transformation from columnar crystals to equiaxed crystals. In addition, the microhardness was improved due to fine grain strengthening and solid solution strengthening. The friction coefficient and cross-sectional area of the composite coating were 0.381 and 8164.732 μm², which was 0.846 and 0.603 times that of the 316L coating, respectively. Moreover, severe adhesive wear and plastic deformation was transformed into slight adhesive wear and abrasive wear due to the addition of TiC and NbC particles. This study provides new approaches to improving the wear resistance of 316L stainless steel and broadens its application.

This work presents a computational protocol, based on a variance analysis integrated with the bootstrap method, to investigate surface damage resulting from localization of plastic deformation in slip bands of a Ni-base superalloy. For assessment of fatigue crack initiation, surface roughness is introduced to quantify the degree of slip irreversibility. The contribution of this study is to provide a most relevant roughness parameter that can extract the salient features of slip bands within damaged grains, and thus enabling the discrimination of damaged and undamaged grains for description of fatigue-induced surface damage. Results suggest that the maximum peak height (S-p) is the most relevant parameter. And a very pronounced variability of S-p values is observed for damaged grains.

As austempered ductile iron (ADI) is a key gear material for meeting the lightweight and cost-effective demands of new energy vehicles, its bending fatigue performance has a direct impact on vehicle transmission efficiency. In the present work, QTD 800 gears were subjected to bending fatigue testing using a combination of the conventional group method and the staircase method, with considerations given to fatigue life and fatigue limit at different reliability levels. Subsequently, the gears were characterized using optical microscopy and a microhardness tester to examine their metallographic structure and determine their hardness. The results indicate that the bending fatigue limits corresponding to gear reliability levels of 50%, 90%, and 99% are 390.00 MPa, 372.55 MPa, and 358.32 MPa, respectively. It was also observed that higher gear life stability corresponds to a lower sustainable fatigue limit stress. The analyses further reveal that under low loads, the main crack exhibits a relatively straight and smooth propagation trajectory, formed through the slow extension of an existing crack, whereas under high loads, the main crack displays a rough and serrated appearance, arising from the coalescence of microcracks initiated around graphite nodules.

The cyclic deformation behavior of gradient structured 316L austenitic stainless steels produced by shot-peening is investigated. The experimental results show that for all specimens, the cyclic response exhibits a similar fundamental evolutionary character, i.e., first cyclic hardening then followed by cyclic softening. The presence of a gradient structured surface layer is observed to be capable of accelerating the cyclic hardening process but decelerating the cyclic softening process. It is further suggested that the former can be related to the restricted cyclic hardening ability and the latter to the high plastic deformation uniformity.