Stress Corrosion Research Articles

Bioactive Glass for Applications in Implants: A Review

AbstractTraditional metallic biomaterials including titanium and its alloys, stainless steel, cobalt‐chromium alloys, magnesium alloys are gold standards for load bearing hard tissue applications, because of adequate mechanical properties such as elastic modulus, ductility and strength for long term support and stability. However, metallic implants suffer from poor osteointegration and early degradation in host body, owing to an array of factors which include stress shieling effect, corrosion, metal toxicity, microbial contamination and low bioactivity. Therefore, to improve integration of implants with host tissue and overall mechanical and biological functions, metallic implants are coated with bioactive glasses (BG). BG are one of the most promising implant coating materials used for bone repair and reconstruction, mainly because of excellent angiogenic, osteoconductive, osteoinductive, corrosion resistance, resorbability, biocompatibility, bioactivity and anti‐microbial properties. Various BG compositions are employed for diverse biomedical applications ranging from wound healing, bone formation, corrosion resistance, drug delivery to scaffolds in tissue engineering and different methods are used for coating BG on implants to enhance stability and bond strength between implant and coating. This narrative review gives a detailed overview on metallic implants, issues of metal alloys when used in implants and how metallic implants are improved by various BG compositions and coating methods. This review provides an updated information on advantages of different BG compositions in implants fabrication in order to address challenges and tailor mechanical and biological properties of implants for future applications.

Superelasticity with narrow stress hysteresis and high cyclic stability in Co–V–Al polycrystalline alloy

Superelasticity of shape memory alloy associated with the martensitic transformation is extremely attractive for applications in sensors and biomedical. This application requires narrow stress hysteresis to reduce energy dissipation and a stable superelasticity cycle is an important factor in their practical applications. Co–V–Al alloys have inimitable advantages due to their narrow stress hysteresis, low-cost, and corrosion resistance, but the low number of superelasticity cycles restricts its development. Here, we report an intrinsic Co58V29Al13 polycrystalline alloy with a superelasticity stress hysteresis of 30 MPa at room temperature, the lowest among the alloys in this system, and a superelasticity strain of 3.6%. In addition, the sample shows no significant decay trend after 500 loading and unloading cycles. The high number of superelasticity cycles is mainly due to the elastic stress field generated around the dislocation during the cycle, which provides internal stress for martensite nucleation and reduces energy dissipation during martensitic transformation. This work provides essential guiding significance for the design of high-performance superelasticity alloys.

Investigation of Stress Corrosion Cracking in CMSX-4 Turbine Blade Alloys Using Deep Learning Assisted X-ray Microscopy and Correlative Imaging Workflow

Investigation of Stress Corrosion Cracking in CMSX-4 Turbine Blade Alloys Using Deep Learning Assisted X-ray Microscopy and Correlative Imaging Workflow

Effect of shot peening on surface characteristics and high-temperature corrosion behaviour of super 13Cr martensitic stainless steel

Super 13Cr, as an economy stainless steel (SS) for oil country tubular goods, needs stable corrosion resistance in high-pressure and high-temperature (HPHT) downhole medium. Severe plastic deformation (SPD) are the surface modification technology to improve mechanical properties, fatigue behavior and corrosion resistance of metals, and shot peening (SP) has been the most widely used SPD process. However, there are quite limited studies about the microsutructure evolution, residual stress, and high-temperature corrosion behavior of SP-treated martensitic SS. In this study, super 13Cr martensitic SS was treated by SP with various air pressures and nozzle speeds. The surface characteristics and high-temperature corrosion behaviour in 3.17 mol/L K2HPO4 solution were investigated through finite element model analysis, characterization of residual stress and microstructure, as well as electrochemical and stress corrosion cracking (SCC) tests at 160 °C and 10 MPa. The results showed that SP-treated super 13Cr could generate high-level compressive residual stress and SPD microstucture, including nano-sized equiaxed grains, gradient lamellar structure and fragmented carbides. Increasing air pressure contributed to achieve uniform nanocrystalline, but tended to generate high dislocation density and surface defects. The improving effect of SP treatment at low air pressure of 0.15 MPa on passivation ability was limited, and high air pressure adversely impacted corrosion resistance. SP-treated specimens showed high SCC susceptibility, due to the introduction of more surface defects, high angle grain boundaries, and dislocations.

A hybrid machine learning strategy for pitting probability prediction of stainless steels

Pitting corrosion represents a substantial threat to passive metals, potentially leading to stress-corrosion cracking and the abrupt failure of materials. The complex relationship between the internal alloy compositions and external environmental factors complicates the precise prediction of pitting probability. In this study, a hybrid machine learning strategy is developed to predict the probability and boundary of pitting corrosion in stainless steel, considering the collaborative effects of different factor pairs rather than a single factor. The strategy integrates both black-box (adaptive boosting) and white-box (symbolic classification) algorithms, where the former is constructed to determine the pitting probability with an F1 score of 0.85, and the latter is designed to achieve recognition of critical factor pairs. This work aims to offer a systematic diagram and new insights in understanding and optimizing the pitting resistance of stainless steel.

Mitigation of Stress Corrosion Cracking in Additively Manufactured Stainless Steel by Laser Shock Peening

Mitigation of Stress Corrosion Cracking in Additively Manufactured Stainless Steel by Laser Shock Peening

Investigation into Effects of Coating on Stress Corrosion of Cable Bolts in Deep Underground Environments.

Due to the intricate and volatile nature of the service environment surrounding prestressing anchoring materials, stress corrosion poses a significant challenge to the sustained stability of underground reinforcement systems. Consequently, it is imperative to identify effective countermeasures against stress corrosion failure in cable bolts within deep underground environments, thereby ensuring the safety of deep resource extraction processes. In this study, the influence of various coatings on the stress corrosion resistance of cable bolts was meticulously examined and evaluated using specifically designed stress-corrosion-testing systems. The specimens were subjected to loading using four-point bending frames and exposed to simulated underground corrosive environments. A detailed analysis and comparison of the failure patterns and mechanisms of specimens coated with different materials were conducted through the meticulous observation of fractographic features. The results revealed stark differences in the stress corrosion behavior of coated and uncoated bolts. Notably, epoxy coatings and chlorinated rubber coatings exhibited superior anti-corrosion capabilities. Conversely, galvanized layers demonstrated the weakest effect due to their sacrificial anti-corrosion mechanism. Furthermore, the effectiveness of the coatings was found to be closely linked to the curing agent and additives used. The findings provide valuable insights for the design and selection of coatings that can enhance the durability and reliability of cable bolts in deep underground environments.

Intergranular corrosion and stress corrosion cracking properties evaluation and mechanism study of multi-microalloyed 2519 Al alloy

In this paper, the microstructure of the alloy has been modulated by the multivariate microalloying technique, aiming to reveal the intrinsic relationship and mechanism of intergranular corrosion and stress corrosion cracking. The addition of V to 2519 alloy changed the distribution characteristics of grain boundary precipitates and the dislocation density was reduced by 22.5 %, and the intergranular and stress corrosion cracking properties of the alloy were improved by 14.1 % and 40.7 %, respectively. Interestingly, grain deflection with <XXY>/48°-58° axial angle relationship was found during stress corrosion crack propagation and the alloy had the best stress corrosion resistance.

Metallurgical failure investigation of small bore piping (SBP) in a diesel hydrotreating unit (DHT) of an oil refinery

Abstract Hydrocarbon leaks were repeatedly found in the client’s refinery. Because of the recurring nature of this failure, the operator approached the authors’ laboratory to get a second opinion on the metallurgical root cause of the failure. It was known from the customer that corrosive species, such as ammonium chloride salt precipitates, are present in the subject diesel hydrotreating unit (DHT). From the findings obtained in the investigation that is the subject of this contribution, the conclusion of the original metallurgical root cause analysis (RCA), namely that the subject piping failed by transgranular chloride-induced stress corrosion cracking (Cl-SCC), could be verified and is indeed correct. The metallurgical root cause of the small bore piping (SBP) failure is chloride-induced SCC. The morphology of the cracking is very distinct and is clearly consistent with transgranular Cl-SCC. A material change to the nickel-base material Alloy 625, already considered by the client, since this alloy is believed to be immune to chloride-induced SCC, would be a good, even though expensive solution. It should be emphasized that there are no metallic materials completely resistant to SCC. If the environment is harsh enough, except for some titanium alloys, i. e., if the source of the chloride ions cannot be eliminated, which is likely the case here, a regular inspection and replacement of these SBP systems might have to be considered. It should further be emphasized that a chloride concentration below 50 ppm is by no means any guarantee for the avoidance of SCC, since chlorides can concentrate in crevices, corrosion pits and such, i. e., the local concentration is what matters, not the local.

The impact of loading rate on chloride induced stress corrosion cracking of 304L stainless steel

Abstract The influence of applied loading rate (dK/dt) on stress corrosion cracking (SCC) behavior in annealed 304L stainless steel immersed in 4.7 M MgCl2 solution was assessed at varying temperatures from 23 °C to 70 °C. Measured crack growth rates obtained under rising K loading (dK/dt &gt; 0) are compared to those obtained during static K testing. A rising K-based loading protocol was found to yield more conservative crack growth rates across all temperatures, with the variation in crack growth rates (and therefore the dependence in loading rate) decreasing with increasing environmental severity.

A Time-Dependent Damage Constitutive Model for Brittle Rock Materials Based on Subcritical Damage Theory.

In the domain of geotechnical engineering, a profound understanding of the long-term mechanical deformation characteristics of rocks is indispensable for the design and construction of structures, dams, tunnels, and various engineering projects. The deformation behavior of rocks under long-term loads directly impacts the stability and safety of engineering structures. This study employs micromechanical methods to investigate the subcritical extension of microcracks under stress corrosion. By examining the accumulated damage resulting from this phenomenon, the research explores the patterns of aging damage development and establishes a constitutive model for aging that incorporates cumulative damage over the stress history. The accuracy of the proposed model is evaluated through a comprehensive comparison of numerical results with experimental data. The experimental data set encompasses traditional triaxial compression tests, single-stage creep, multistage creep, and single-stage relaxation tests conducted under varying confining pressures. The predicted results exhibit strong consistency with the entire data set. Furthermore, this paper employs crack damage stress as an indicator characterizing the long-term strength of rock. Through frictional damage coupling analysis and derivation, an analytical expression for the long-term strength of rock materials containing microcracks is provided, serving as a theoretical basis for investigating the long-term mechanical performance of brittle rock materials and ensuring the long-term stability of large-scale rock engineering projects.

Effect of Boron on Stress Corrosion Resistance of S31254 Super‐Austenitic Stainless Steel After Cold Deformation

The effect of boron (B) on stress corrosion resistance of S31254 in the presence of residual stresses has been studied. The microstructure and corrosion resistance of S31254 containing B at different levels of cold deformation are analyzed in this study. In the results, it is shown that B favors the improvement of deformation uniformity of S31254. The grain boundary (GB) and slip bands have better corrosion resistance at 5% deformation, and the overall corrosion resistance is better than that of the undeformed state, with smaller passivation current density and narrower width of GB corrosion grooves, especially for the 40B samples. At 30% deformation, the overall corrosion resistance of 40B S31254 is better than 0B due to improved deformation uniformity.

Revisiting Ag addition in 7xxx aluminum alloys: Insights into its impact on the microstructure and properties of an Al-Zn-Mg-Cu-Zr alloy with a Zn/Mg ratio of 4

In this study, the influence of minor Ag addition on the microstructure, mechanical and corrosion properties of an Al-Zn-Mg-Cu-Zr (7449) alloy with Zn/Mg ratio of 4 was systematically investigated using various materials characterization techniques, Slow Strain Rate Test (SSRT), Potentiodynamic Polarization (PDP) and Intergranular Corrosion (IGC) measurements. Microstructure characterization by Scanning Electron Microscopy (SEM) and Differential Scanning Calorimetry (DSC) showed that Ag partitioning in the eutectic Mg(Zn,Cu,Al)2 phase occurs resulting in an increase in its solvus line. After processing to the T4 condition, Ag was partially in solid solution with the excess forming an Ag-rich AlAgZnMgCu phase. Scanning-Transmission Electron Microscopy (STEM) showed evidence of quench-induced η-Mg(Zn,Cu,Al)2 precipitates at the grain boundaries (GBs) in the T4 condition with ∼3 at.% Ag in the Ag-modified alloy. STEM and Atom Probe Tomography (APT) confirmed that ∼1 at. % Ag was present in both the matrix and GB precipitates in the Ag-modified alloy after T76 aging. Furthermore, the frequently reported decrease in the PFZ width with Ag addition was not observed after T76 aging, with both alloys having a similar PFZ width. Despite higher hardness/strength in the T4 condition with Ag addition, no enhanced age hardening response and alteration of the precipitation kinetics was observed during artificial aging at 121 °C. In fact, Ag addition in a 7xxx alloy with Zn/Mg ratio of 4 was found to be detrimental to mechanical properties, stress corrosion cracking, pitting and IGC resistance after T76 aging, which is attributed to the presence of the Ag-rich AlAgZnMgCu phase.

Pipeline Circumferential Cracking in Near-Neutral pH Environment Under the Influence of Residual Stress: Dormancy and Crack Initiation

The purpose of this study is to identify the integrity challenges encountered by buried pipeline steels, specifically to address Circumferential Near-Neutral pH Corrosion Fatigue (C-NNpH-CF). Damage to the pipeline’s protective coating and corrosion conditions increase the risk of service failures caused by C-NNpH-CF. (Note that this mechanism has previously been termed near-neutral pH stress corrosion cracking.) Unlike axial cracking, circumferential cracking is primarily influenced by residual stress from pipeline bending, geohazards, and girth welds. External corrosion pits often lead to dormant cracks, with growth ceasing around 1 mm depth due to reduced dissolution rates. Investigating the impact of bending residual stress (an appropriate source of axial residual stress) and cyclic loading (simulated pipeline pressure fluctuation), the study employs the digital image correlation (DIC) method for stress distribution analysis. Factors like applied loading, initial notch depth, and bending conditions influence crack initiation and recovery from the dormancy stage by affecting stress distribution, stress cells, and stress concentration. Cross-sectional and fractographic images reveal time/stress-dependent mechanisms governing crack initiation, including dissolution rate and hydrogen-enhanced corrosion fatigue. The study emphasizes the role of various residual stress types and their interactions with axial cyclic loading in determining the threshold conditions for crack initiation.

Stress-Corrosion-Cracking Sensitivity of the Sub-Zones in X80 Steel Welded Joints at Different Potentials.

X80 steel plays a pivotal role in the development of oil and gas pipelines; however, its welded joints, particularly the heat-affected zone (HAZ), are susceptible to stress corrosion cracking (SCC) due to their complex microstructures. This study investigates the SCC initiation mechanisms of X80 steel welded joints under practical pipeline conditions with varying levels of cathodic protection. The SCC behaviors were analyzed through electrochemical measurements, hydrogen permeation tests, and interrupted slow strain rate tensile tests (SSRTs) conducted in a near-neutral pH environment under different potential conditions (OCP, -1.1 VSCE, -1.2 VSCE). These behaviors were influenced by microstructure type, grain size, martensite/austenite (M/A) constituents, and dislocation density. The sub-zones of the weld exhibited differing SCC resistance, with the fine-grain (FG) HAZ, base metal (zone), welded metal (WM) zone, and coarse-grain (CG) HAZ in descending order. In particular, the presence of coarse grains, low dislocation density, and extensive M/A islands collectively increased corrosion susceptibility and SCC sensitivity in the CGHAZ compared to other sub-zones. The SCC initiation mechanisms of the sub-zones within the X80-steel welded joint were primarily anodic dissolution (AD) under open-circuit potential (OCP) condition, shifting to either hydrogen-enhanced local plasticity (HELP) or hydrogen embrittlement (HE) mechanisms at -1.1 VSCE or -1.2 VSCE, respectively.

Improving intergranular cracking and stress corrosion cracking resistance of highly sensitized AA5083 Al-Mg alloy via reversion heat treatment

This study systematically examines the impact of reversion heat treatments (220–280 ℃ for 1 h) on the microstructure evolution, electrochemical corrosion, intergranular cracking (IGC) and stress corrosion cracking (SCC) of a severely sensitized (175 ℃/100 h) AA5083 alloy. Increasing the reversion temperature gradually enhances the corrosion resistance by dissolving the β′-Al3Mg2 phase, with the optimal treatment identified as 280 ℃/1 h. The βˊ phase maintains its planar film shape and continuously covers the grain boundaries after reversion treatment below 240 °C, but spheroidizes at the triple junctions at 260 °C. The morphology of the βˊ phase is dictated by grain boundary diffusion and interface diffusion. Reversion treatments improve SCC resistance by dissolving the β′ phase and reducing yield strength, attributed to anodic dissolution and hydrogen embrittlement mechanisms. This research offers valuable insights into the practical benefits of reversion treatments for Al-Mg alloy marine applications, addressing safety concerns related to sensitization.

Influences of (Al, Ca, Si, Nb, Mn)-oxy-sulfide inclusions on corrosion degradation for newly designed 17–4 martensitic PH steel in simulated geothermal environments

Influences of (Al, Ca, Si, Nb, Mn)-oxy-sulfide inclusions on hydrogen trapping and stress corrosion cracking in a newly designed 17–4 martensitic PH steel were carried out under simulated geothermal environments based on experiments and calculations. The results indicate that CaS and MnS in inclusions are not only prone to preferential dissolution, but also more likely to become hydrogen trapping sites at the interface with matrix than other components. The number of pits rapidly increase before the sample fracture at 159.25 h, while cracks around external pits and internal gourd-like cavities are probably attributed to the uneven expansion of inclusion-triggered pits.

Improved Tensile Strength and SCC Resistance via Nonisothermal Creep Aging under a High Stress Level

Compared with conventional isothermal creep aging (ICA), non‐ICA (NICA) does not involve a prolonged holding stage, but only has heating and cooling stages. During the NICA process, the precipitates nucleate and grow up in the early part of heating stage, resulting in fluctuations in creep rate and an increase in strength. The coarsening of precipitates in the later part of the heating stage can lead to significant increase of creep rate. Upon approaching the peak temperature, the dissolution of the precipitates occurs in conjunction with a partial coarsening of the remaining precipitates, causing a reduction in strength. However, the secondary precipitation during the cooling stage facilitates a significant strength enhancement in a relatively shorter period. In contrast to the ICA, the targeted NICA treatment gives an increase in ultimate strength while improves the stress corrosion cracking resistance. Moreover, the time required for NICA to obtain ultimate strength is only 13.9% of that of the ICA treatment. A large amount of creep strain can be generated during the NICA process, which is equivalent to 630% of that of creep age forming treatment.

Development of a Dezincification-Free Alloy System for the Manufacturing of Brass Instruments

Conventionally used brass alloy CuZn30 shows problems with corrosion resistance in the form of dezincification when used in brass instruments. Therefore, within the scope of this investigation, a new brass alloy CuZn30 is developed in the microalloy range with corrosion-free or corrosion-inhibiting properties. First, the influence of microalloying elements on the phase composition is investigated by simulation using Thermo-Calc. On the basis of this, suitable alloying elements and contents are selected and a modified CuZn30X alloy with 0.1% phosphorus, tin, and nickel in mass fractions, respectively, is produced. The modified alloy is then investigated with regard to its mechanical and microstructural composition and its corrosion properties. The corrosion properties were examined using stress corrosion cracking tests, dezincification tests, and the recording of polarization curves. The modified alloy exhibited good cold and hot rolling properties as well as good corrosion resistance. The dezincification test confirmed the improved corrosion resistance of the modified CuZn30X alloy, which is attributed to the formation of a protective top layer due to the alloying elements.

Comprehensive Review on the Flexure Behaviour of Corroded Reinforcement Concrete Beams Under Sustained Loads

This study presents a comprehensive review of the flexural behaviour of corroded Reinforced Concrete (RC) beams subjected to sustained loads. The investigation synthesizes extant literature to elucidate the complex interaction between concurrent stress and steel corrosion in RC members. Emphasis is placed on the critical necessity of conducting corrosion tests under continuous stress conditions to accurately simulate in-situ structural behaviour. The review encompasses previous numerical studies on deteriorated RC beam performance and provides a critical analysis of historical loading regimes designed to mitigate corrosion in loaded RC beams. Notably, the literature reveals conflicting findings regarding the influence of loading on corrosion rates and crack propagation, highlighting areas necessitating further research. The review also considers the effects of creep, shrinkage, and stress, with particular emphasis on long-term deflection characteristics. This comprehensive analysis aims to consolidate current knowledge and identify critical research gaps in understanding the flexural behaviour of corroded RC beams under sustained loads, thereby providing a foundation for future investigations in this domain.