Effect of temperature upon stress corrosion cracking of HY-180M steel in 3.5 Pct NaCI

A fracture mechanics and fractographic study of stress corrosion cracking (SCC) of heat treated HY-180 M steel was undertaken over the temperature range 22 to 95 °C at applied potentials of −0.28 V_SHE (−0.48 V_Ag/AgCl) and −0.80 V_SHE (−1.0 V_Ag/Agcl). Particular attention was directed toward Region II behavior, where crack propagation rates were independent of stress intensity(K _l). Region II rates were always higher at the less noble potential of −0.80 V_SHE than at the more noble potential of — 0.28 V_SHE. However, fractography studies suggested that the basic mechanism of cracking at both potentials was the same, and involved hydrogen embrittlement. An Arrhenius analysis of Region II rates showed that crack propagation was under the control of more than one process. Consequently, the mechanistic details remained obscure. Formerly Research Associate in theDepartment of Metallurgical Engineering, University of BritishColumbia.     

Caustic Stress Corrosion Cracking of Mild Steel

The stress corrosion cracking (SCC) behavior of cold worked mild steel in hot, aqueous, 33 pct NaOH solutions was studied with prefatigue cracked double cantilever beam specimens. SCC kinetics were studied under freely corroding potentials (E _corr ≈ −1.00 V_SHE) and potentiostatic potentials of −0.76 V_SHE near the active-passive transition. The pH of the liquid within the crack was determined and fractography was studied by scanning electron microscopy. Cracking was transgranular atE _corr, intergranular at −0.76 V_SHE, and produced no detectable change in crack liquid pH from that of the bulk solution. Crack rates were dependent upon temperature, potential, and stress intensity (K ₁). The apparent activation energy in Region II, where crack growth rate was independent ofK, was ∼ 24kJ/mol for both cracking modes. This was considered to be due to mixed rate control involving activation polarization and mass transport processes. The mechanism of cracking was entirely consistent with metal dissolution at –0.76 V_SHE and may involve hydrogen embrittlement and/or dissolution effects atE _corr. DOUGLAS SINGBEIL, formerly Research Student, University of British Columbia, is Research Scientist, Pulp and Paper Research Institute of Canada, 570-Blvd. St. Jean, Pointe Claire, Quebec, Canada H9R 3J9.     

Stress corrosion cracking of high strength HY-180M steel in 3.5 Pct NaCl

Stress corrosion cracking of HY-180M steel was studied at 22°C in an aqueous solution of 3.5 pct NaCl (pH = 6.5). The steel had a nominal weight percentage composition of 10Ni-14Co-2Cr-lMo-0.16C and was heat treated to yield a fracture toughness value ofK _Ic ≃ 160 MPa . m^1/2. The SCC velocity (v) was studied as a function of stress intensity (K _I) and electrochemical potential (E) using precracked compact tension specimens, a Ag/AgCl reference electrode and a 1000 h exposure test. Also, the polarization behavior, microstructure, fractography and corrosion products were studied. The results showed that SCC was markedly dependent uponE, and did not occur whenE =-0.52 V_SHE (-0.72 V_Ag/AgCl), which corresponded closely to the thermodynamically reversible potential of iron. However, SCC occurred at a more noble potential of-0.28 V_SHE (-0.48 V_Ag/AgCl ) and at a less noble potential of-0.80 V_SHE (-1.00 V_Ag/AgCl). The stress intensity below which SCC was not observed was K_ISCC ≃ 5.5 MPa . m^1/2 at -0.28 V_SHE and K_ISCC ≃ 60 MPa . m^1/2 at -0.80 V_SHE . Also, Region I behavior (v dependent uponK ₁) and Region II behavior (v independent ofK ₁) were observed. Cracking was considered to occur solely by hydrogen embrittlement at -0.80 Vshe, whereas anodic dissolution processes played a necessary role, either directly or indirectly, in SCC at -0.28 V_SHE . The indirect effects were discussed in relation to hydrolysis effects in the crack promoting hydrogen embrittlement and/or corrosion product wedging stresses.     

Effect of overaging on mechanical properties and stress corrosion cracking of HY-180M steel

The tensile properties, fracture toughness and stress corrosion cracking (SCC) behavior of HY-180 M steel at 22 °C were studied after final 5 h overaging treatments >510 ≤650 °C. SCC tests were conducted for 1000 h with compact tension specimens in aqueous 3.5 pct NaCl solutions at a noble (anodic) potential of −0.28 V_SHE ( −0.48 V_Ag/AgC1) and a cathodic protection potential of −0.80 V_SHE (−1.0 V_Ag/AgC1). The SCC resistance improved at aging temperatures >565 °C, the most significant improvement being at −0.80 V_She, especially after 650 ° aging whereK _ISCC was raised to at least 110 MPa · m^1/2. However, this was at the expense of mechanical properties. Provided low crack propagation rates of ∼3 X 10⁻¹¹ m/s at −0.80V _SHEmay be tolerated, the best compromise between strength, toughness, and SCC resistance was obtained after 594 °C aging. Under these conditions, stress intensities as high as ∼ 110 MPa · m^1/2 can be used, with a yield strength of ∼ 1150 MPa and fracture toughness of ∼ 170 MPa · m^1/2. The retained austenite content after aging increased with aging temperature up to 25 pct by vol at 650 °C. It appeared to correlate with improved SCC resistance, but other microstructural effects associated with aging may be involved. Formerly Research Associate with theDepartment of Metallurgical Engineering , University of BritishColumbia     

Initiation of stress corrosion cracking for pipeline steels in a carbonate-bicarbonate solution

The linearly increasing stress test (LIST) was used to study the stress corrosion cracking (SCC) behavior of a range of pipeline steels in carbonate-bicarbonate solution under stress rate control at different applied potentials. Stress corrosion cracking, at potentials below -800 mV(SCE), was attributed to hydrogen embrittlement. Stress corrosion cracking, in the potential range from about-700 to -500 mV(SCE), was attributed to an anodic dissolution mechanism. In the anodic potential region, the SCC initiation stress was larger than the yield stress and was associated with significant plastic deformation at the cracking site. The relative SCC initiation resistance decreased with in-creasing yield strength. In the cathodic potential region, the SCC initiation stress was smaller than the yield stress of steel; it was approximately equal to the stress at 0.1 pct strain(@#@ Σ_0.1pct) for all the steels. The original surface was more susceptible to SCC initiation than the polished surface.     

Stress corrosion cracking of beta-brasses in water

Stress corrosion cracking (SCC) ofβ ^’-phase brasses in water at 20 °C was studied in four Cu-Zn binaries and one Cu-Zn-Sn ternary alloy using slow strain rate tensile tests and load relaxation SCC of notched rods. Electron diffraction techniques were used to identify phases on the fracture surfaces. All alloys were susceptible to SCC and it was found that decreasing the electron/atom(e/a) ratio of theβ ^’-phase promoted transgranular SCC and increased the rate of cracking. The most rapid crack propagation rates were associated with alloy compositions giving rise to a strain induced martensite transformation during SCC. Formerly Graduate Student at the University of British Columbia     

Role of Mg in the stress corrosion cracking of an Al-Mg alloy

The corrosion and stress corrosion cracking (SCC) susceptibility of an Al-Mg alloy, AA5083, has been shown to depend on the precipitation of the Mg-rich β phase, (Al₃Mg₂), but not the enrichment of elemental Mg at grain boundaries to an enrichment ratio of 1.4. These results were determined by measuring the progress of Mg enrichment at grain boundaries, for increasing thermal-treatment times, using auger electron spectroscopy (AES) of grain boundaries exposed by fracture within the spectrometer and by analytical electron microscopy (AEM) of thin foils. The progress of the β phase precipitation was followed by AEM and scanning electron microscopy (SEM), for the same thermal-treatment times. The lack of a Mg-segregation effect on SCC was demonstrated by results obtained with X-ray photoelectron spectroscopy (XPS) analysis of Mg-implanted Al following in-situ electrochemical tests and SCC tests, while the dominance of β phase precipitation was demonstrated by electrochemical analysis and SCC testing. Crack-growth tests of alloy AA5083 demonstrated faster cracking at potentials anodic to the open circuit potential (OCP) with no increase at potentials cathodic to the OCP.     

Stress corrosion cracking of pressure vessel steels in high-temperature caustic aluminate solutions

Stress corrosion cracking (SCC) behavior of three kinds of low alloy pressure vessel steels in high-temperature (200 °C to 300 °C) caustic aluminate (AIO_-2) solutions has been studied by slow strain rate tests (SSRT). The results indicate that these pressure vessel steels are susceptible to SCC in caustic aluminate solution and that the SCC susceptibility increases with increasing temperature between 200 °C to 300 °C. Sulfide content and stringered sulfide inclusions severely and anisotrop-ically affect the caustic SCC of these low alloy steels. The inclusions in the rare-earth-treated steel are predominantly globular rare-earth sulfides or oxysulfides, resulting in improved transverse prop-erties. The effect of inclusions on SCC behavior correlates with the projected area of inclusions perunit volume at the crack tip,A _v , on the plane perpendicular to the tensile direction. The susceptibility to SCC increases with increasingA _v .     

The effect of cathodic polarization on the corrosion fatigue behavior of a precipitation hardened aluminum alloy

Fatigue experiments were conducted on polycrystalline and monocrystalline samples of a high purity Al, 5.5 wt pct Zn, 2.5 wt pct Mg, 1.5 wt pct Cu alloy in the peak-hardened heat treatment condition. These experiments were conducted in dry laboratory air and in 0.5N NaCl solutions at the corrosion potential and at applied potentials cathodic to the corrosion potential. It has been shown that saline solutions severely reduce the fatigue resistance of the alloy, resulting in considerable amounts of intergranular crack initiation and propagation under freely corroding conditions for polycrystalline samples. Applied cathodic potentials resulted in still larger decreases in fatigue resistance and, for poly crystals, increases in the degree of transgranular crack initiation and propagation. Increasing amounts of intergranular cracking were observed when applied cyclic stresses were reduced (longer test times). The characteristics of cracking, combined with results obtained on tensile tests of deformed and hydrogen charged samples, suggest that environmental cracking of these alloys is associated with a form of hydrogen embrittlement of the process zones of growing cracks. Further, it is suggested that stress corrosion cracking and corrosion fatigue of these alloys occurs by essentially the same mechanism, but that the often observed transgranular cracking under cyclic loading conditions occurs due to enhanced hydrogen transport and/or concentrations associated with mobile dislocations at growing crack tips.     

The effects of heat treatment on the chromium depletion,precipitate evolution,and corrosion resistance of INCONEL alloy 690

A series of heat treatments were performed to study the sensitization and the stress corrosion cracking (SCC) behavior of INCONEL Alloy 690. The microstructural evaluation and the chromium depletion near grain boundaries were carefully studied using analytical electron microscopy (AEM). The measured chromium depletion profiles were matched well to the calculated results from a thermodynamic/kinetic model. The constant extension rate test (CERT) was performed in the solution containing 0.001 M sodium thiosulfate (Na₂S₂O₃) to study the SCC resistance of this alloy. The Huey test was also performed in a boiling 65 pct HNO₃ solution for 48 hours to study the intergranular attack (IGA) resistance of this alloy. Both tests showed that INCONEL 690 has very good corrosion resistance. It is believed that the superior IGA and SCC resistances of this alloy are due to the high chromium concentration (≈30 wt pct). It is concluded in this study that INCONEL 690 may be a better alloy than INCONEL 600 for use as the steam generator (S/G) tubing material for pressurized water reactors (PWR's)     

Stress corrosion cracking relation with dezincification layer-induced stress

Brass foil with a protective layer formed on one side was deflected during corrosion in an ammonia solution under various applied potentials, and then corrosion-induced stress generated at brass/dezincification layer under different potentials could be measured. At the same time, susceptibility to stress corrosion cracking (SCC) of brass in the ammonia solution under various applied potentials was measured by using a single-edge notched specimen. At open-circuit potential, both corrosion-induced tensile stress and susceptibility to SCC (I _σ) had a maximum value. Both tensile stress σ _p and susceptibility I _σ decreased slightly with decreasing potential under anodic polarization, but reduced steeply with a decrease in potential under cathodic polarization. At the cathodic potential of − 500 mV_SCE, corrosioninduced stress became compressive because of the copper-plating layer; correspondingly, susceptibility to SCC was zero. Therefore, the variation of SCC susceptibility with potential is consistent with that of the corrosion-induced additive stress.     

Effect of Repair Welding on Electrochemical Corrosion and Stress Corrosion Cracking Behavior of TIG Welded AA2219 Aluminum Alloy in 3.5 Wt Pct NaCl Solution

The stress corrosion cracking (SCC) behavior of AA2219 aluminum alloy in the as-welded (AW) and repair-welded (RW) conditions was examined and compared with that of the base metal (BM) in 3.5 wt pct NaCl solution using the slow strain rate technique (SSRT). The reduction in ductility was used as a parameter to evaluate the SCC susceptibility of both BM and welded joints. The results show that the ductility ratio (ε _NaCl/(ε _air)) of the BM was close to one (0.97) and reduced to 0.9 for the AW joint. This value further reduced to 0.77 after carrying out one repair welding operation. However, the RW specimen exhibited higher ductility than the single-weld specimens even in 3.5 wt pct NaCl solution. SSRT results obtained using pre-exposed samples followed by post-test metallographic observations clearly showed localized pitting corrosion along the partially melted zone (PMZ), signifying that the reduction in ductility ratio of both the AW and RW joints was more due to mechanical overload failure, caused by the localized corrosion and a consequent reduction in specimen thickness, than due to SCC. Also, the RW joint exhibited higher ductility than the AW joint both in air and the environment, although SCC index (SI) for the former is lower than that of the latter. Fractographic examination of the failed samples, in general, revealed a typical ductile cracking morphology for all the base and welded joints, indicating the good environmental cracking resistance of this alloy. Microstructural examination and polarization tests further demonstrate grain boundary melting along the PMZ, and that provided the necessary electrochemical condition for the preferential cracking on that zone of the weldment.     

Stress Corrosion Cracking Behavior of Multipass TIG-Welded AA2219 Aluminum Alloy in 3.5?wt?pct NaCl Solution

The stress corrosion cracking (SCC) behavior of the AA2219 aluminum alloy in the single-pass (SP) and multipass (MP) welded conditions was examined and compared with that of the base metal (BM) in 3.5?wt?pct NaCl solution using a slow-strain-rate technique (SSRT). The reduction in ductility was used as a parameter to evaluate the SCC susceptibility of both the BM and welded joints. The results showed that the ductility ratio (?? _NaCl/(?? _air) was 0.97 and 0.96, respectively, for the BM and MP welded joint, and the same was marginally reduced to 0.9 for the SP welded joint. The fractographic examination of the failed samples revealed a typical ductile cracking morphology for all the base and welded joints, indicating the good environmental cracking resistance of this alloy under all welded conditions. To understand the decrease in the ductility of the SP welded joint, preexposure SSRT followed by microstructural observations were made, which showed that the decrease in ductility ratio of the SP welded joint was caused by the electrochemical pitting that assisted the nucleation of cracks in the form of corrosion induced mechanical cracking rather than true SCC failure of the alloy. The microstructural examination and polarization tests demonstrated a clear grain boundary (GB) sensitization of the PMZ, resulting in severe galvanic corrosion of the SP weld joint, which initiated the necessary conditions for the localized corrosion and cracking along the PMZ. The absence of PMZ and a refined fusion zone (FZ) structure because of the lesser heat input and postweld heating effect improved the galvanic corrosion resistance of the MP welded joint greatly, and thus, failure occurred along the FZ.     

A fracture mechanics study of stress corrosion cracking of type-316 austenitic steel

A new test specimen configuration, designated the T-notch double cantilever beam (TNDCB), was developed, calibrated and employed for a fracture mechanics study of stress corrosion cracking (SCC) of cold worked Type-316 austenitic stainless steel exposed to hot aqueous solutions of 44.7 wt pct MgCl₂. The effects of stress intensity (K _I ), temperature (T) and electrochemical potential (E) upon the crack velocity (v) and fractography were investigated. The stress intensity (K _ISCC ) below whichv became immeasurably small was ∼12 MN·m^−3/2. Above this value, three regions of behavior were observed. Region I exhibitedK _I dependent cracking followed by Region II which exhibitedK _I independent cracking and an apparent activation energy of 63 to 67 kJ/mol, followed by Region III where cracking again became dependent uponK _I . The relative proportions of intergranular and transgranular crack paths were markedly dependent upon bothK _I andE, and less sensitive toT. Crack velocity was insensitive to small changes inE with respect to the free corrosion potentials (E _corr), but could be terminated by an applied active potential of ∼−0.35 V_SCE. The pH within the propagating crack was estimated to be <1.0 atE _corr, rising to ∼4.5 at −0.35 V_SCE. The mechanism of SCC was discussed with respect to film rupture events caused by crack tip plastic deformation, adsorption controlled processes on the metal surface, and hydrogen diffusion in the metal lattice. Alan J. RUSSELL, formerly Research Student, University of British Columbia     

Hydrogen embrittlement, grain boundary segregation, and stress corrosion cracking of alloy X-750 in low-and high-temperature water

The nature of intergranular stress corrosion cracking (SCC) of alloy X-750 was characterized in low-and high-temperature water by testing as-notched and precracked fracture mechanics specimens. Materials given the AH, BH, and HTH heat treatments were studied. While all heat treatments were susceptible to rapid low-temperature crack propagation (LTCP) below 150 °C, conditions AH and BH were particularly susceptible. Low-temperature tests under various loading conditions (e.g., constant displacement, constant load, and increasing load) revealed that the maximum stress intensity factors (K _{p max}) from conventional rising load tests provide conservative estimates of the critical loading conditions in highly susceptible heats, regardless of the load path history. For resistant heats, K _{P max} provides a reasonable, but not necessarily conservative, estimate of the critical stress intensity factor for LTCP. Testing of as-notched specimens showed that LTCP will not initiate at a smooth surface or notch, but will readily occur if a cracklike defect is present. Comparison of the cracking response in water with that for hydrogen-precharged specimens tested in air demonstrated that LTCP is associated with hydrogen embrittlement of grain boundaries. Equivalent activation energies for stage II LTCP rates (11.3 kcal/mol) and hydrogen diffusion (11.5 kcal/mol) indicate that hydrogen diffusion to the peak stress region ahead of a crack is the rate-controlling process. Auger analysis showed that variability in LTCP resistance is associated with phosphorus and sulfur segregation to grain boundaries. Above 150 °C, an increase in fracture resistance and decrease in the degree of hydrogen enrichment precludes rapid intergranular cracking. The stress corrosion crack initiation and growth does occur in high-temperature water (>250 °C), but crack growth rates are orders of magnitude lower than LTCP rates. The SCC resistance of HTH heats is far superior to that of AH heats as crack initiation times are two to three orders of magnitude greater and growth rates are one to two orders of magnitude lower.     

Stress corrosion cracking of Ag-20Au in HCLO4, AgCLO4, and KCL solutions by surface mobility

Slow, intermediate, and ultrafast strain-rate experiments were performed on Ag-20Au (atomic percent) wire samples in 1 M HC1O₄, AgClO₄, and KCl solutions. Intergranular stress corrosion cracking was found in all of the solutions tested. In the ultrafast strain-rate experiments, 9.6 s^-1, in HC1O₄ and in AgClO₄ solutions, the size of the cracks proved to be a function of the electric charge circulated before straining. AgClO₄ was also found to specifically induce stress corrosion cracking (SCC) in the Ag-20Au alloy. The surface mobility SCC mechanism was concluded to be the only one that accounted for all of the experimental observations made in the present work.     

Stress-corrosion cracking susceptibility of the superplastically formed 5083 aluminum alloy in 3.5 pct NaCl solution

The slow strain rate test (SSRT) method was employed to study the stress corrosion cracking (SCC) susceptibility of the superplastic 5083 Al alloy in a 3.5 pct NaCl solution after superplastic forming and various heat treatments. Experimental results showed that both superplastically formed specimens and specimens subject to the same thermal processes as that used in superplastic forming suffered severe SCC susceptibility, and obvious intergranular fracture surfaces were also observed. Furthermore, scanning transmission electron microscopy (STEM) and energy-dispersive X-ray spectroscopy (EDS) analyses demonstrated that the thermal processes of superplastic forming led to continuously distributed precipitation layers of β phase (Mg₂Al₃) at grain boundaries, i.e., sensitization had occurred. However, postforming annealing treatment at 345 °C for 1 hour eliminated the sensitization effect of both specimens. In this case, the SCC susceptibility was alleviated, and the fracture surfaces changed to a transgranular dimpled structure, characteristic of that found in the as-received specimen. From the metallographic observations, it was also seen that a number of cavities appeared at the grain boundaries of the superplastically formed specimen. However, the cavitation effect on SCC susceptibility is minor in comparison with the sensitization effect.     

Formation kinetics and rupture strain of Ni-Cr-Fe alloy corrosion films formed in high-temperature water

Nickel alloys such as Alloy 600 undergo stress corrosion cracking (SCC) in pure water at temperatures between about 260 °C and the critical point. Increasing the level of Cr in Ni-Fe-Cr alloys increases SCC resistance in aerated and deaerated water. The mechanism for Cr influence is not understood. The effect of Cr composition on the in-situ oxide rupture strain and corrosion kinetics of Ni-9Fe-Cr alloys was determined experimentally, to evaluate whether the rupture-dissolution model for SCC can account for the effect of Cr on SCC. The alloy corrosion rate and corrosion product oxide microstructure and mechanical properties are strongly influenced by Cr composition. As Cr concentration increases from 5 to 30 pct, oxide rupture strains measured in pressurized water at 288 °C increase from about 8×10⁻⁴ to 2×10⁻³ mm/mm. Corrosion kinetics are parabolic; the corrosion rate first increases and then decreases as Cr increases from 5 to 39 pct. These observations are qualitatively consistent with a rupture-dissolution SCC mechanism. However, parametric modeling of the SCC growth process, applying available creep, oxide rupture strain, and corrosion kinetics data, indicates that the rupture-dissolution mechanism accounts for only a fraction of the effect of Cr on SCC resistance.     

Stress corrosion cracking behaviors of RE-containing ME21 magnesium alloy processed by equal-channel angular pressing

A commercial as-cast ME21 magnesium alloy containing rare-earth (RE) element was processed by equalchannel angular pressing to obtain fine-grained micro structure. Stress corrosion cracking (SCC) behaviors of the fine-grained samples were studied by slow-strain-rate testing in air, distilled water and Hanks’solution at the strain rate of 1×10~(-6) s~(-1). All samples show a relatively low SCC sensitivity in distilled water but a great SCC tendency in Hanks’ solution. The microscopic observations of the fracture surfaces and the side surfaces reveal obvious active anodic dissolution and hydrogen embrittlement cracks, which indicate the higher SCC susceptibility in Hanks'solution. The fine-grained microstructure with more crystal defects promotes the passivation process of the oxide film and restrains the hydrogen induced cracking of the ME21 magnesium alloy, leading to the higher general corrosion resistance as well as SCC resistance.     

The effect of potential and aging on the Pb-assisted stress corrosion cracking susceptibility of alloy 22 gas tungsten arc-welded weldments

The susceptibility of as-received, solutionized, and short-term thermally aged mill-annealed (MA) and gas tungsten arc-welded (GTAW) alloy 22 to Pb-assisted stress corrosion cracking (PbSCC) was evaluated in supersaturated, deaerated, acidic PbCl₂ solutions at 95 °C. Anodic polarization tests in acidic PbCl₂ solutions showed that 16,000 ppm of Pb produced a strong anodic peak and an order of magnitude greater passive current density for both MA and GTAW alloy 22 as compared to pure NaCl solutions. Current spikes were also observed in the anodic polarization plots for the PbCl₂ solutions, suggesting periodic events of passivity breakdown and repassivation. Constant deformation SCC tests were conducted using double U-bend samples of as-received, solutionized, and thermally aged MA and double U-groove welded alloy 22 plates. The results indicate that as-received, solutionized, and thermally aged MA and GTAW alloy 22 were resistant to PbSCC in supersaturated PbCl₂ solutions at 95 °C, pH 0.5, and applied potentials near the anodic peak ranging from −100 to 50 mV_SCE. Enhanced dissolution of alloy 22 was also observed in the crevice region of the double U-bend samples tested in the 16,000 ppm PbCl₂ solutions. This Pb concentration is seven orders of magnitude greater than that found in the anticipated repository environments, and chemical speciation modeling showed that Pb²⁺ is strongly immobilized in J-13 Yucca Mountain waters through the precipitation of PbCO₃ solids. Therefore, although enhanced dissolution of the inner U-bend did occur in our tests, the overall results from this PbSCC investigation suggest that as-fabricated, solutionized, and aged MA and GTAW alloy 22 are resistant to SCC in extremely aggressive, acidic, and supersaturated PbCl₂ solutions at 95 °C. Provided that these high Pb concentrations are not attainable in the anticipated repository environments, alloy 22 is unlikely to be susceptible to SCC, localized corrosion, and enhanced dissolution by the presence of Pb. This article is based on a presentation made in the symposium “Effect of Processing on Materials Properties for Nuclear Waste Disposition,” November 10–11, 2003, at the TMS Fall meeting in Chicago, Illinois, under the joint auspices of the TMS Corrosion and Environmental Effects and Nuclear Materials Committees.