T6 Sample Research Articles

Microstructural evolution and mechanical properties of the rapidly-solidified and hot-extruded 2196 Al-Li alloy

The microstructural evolution and mechanical properties of the 2196 Al-Li alloy prepared by the vacuum gas atomization, hot-isostatic-pressing (HIP) and hot-extrusion were investigated. The results show that prior particle boundaries (PPBs) exist in the microstructure of the HIPed alloy, and hot-extrusion effectively breaks PPBs to restrict the element micro-segregations. The as-extruded alloy exhibits fine grains, and bears higher solution treatment temperature due to the absence of low-melting-point micro-segregations. In the ageing process, the alloy hardness continues to rise, and reaches the peak value at 48 h. The precipitation sequence of the alloy is determined to be: supersaturated solid solution (SSS) → GP zone + fine T1 + δ′ → T1 + θ′ + δ′, where T1 phase dominates the whole ageing process. The diameter of the T1 platelets increases gradually with the increase of ageing time, meanwhile the T1 number density slightly drops in the over-aged alloy. The 3% pre-stretching promotes the nucleation of T1 phase, and the peak-ageing time is shortened to 28 h. Besides, no over-ageing phenomenon is observed in the pre-stretched samples. The Mg-Cu and non-Cu clusters formed on the dislocations accelerate the precipitation of T1 phase and prevent the nucleation of θ′ phase. The yield strength (YS) and ultimate tensile strength (UTS) of the T8 sample are 490 MPa and 515 MPa, respectively, which is notably higher than the T6 sample. The tensile strength of the present alloy is relatively higher than that of the Al-Li alloys with a comparable Li content.

Dry sliding wear behavior of AA7075 alloy produced by thixocasting

Abstract In this study, the wear behavior of AA7075 alloy produced by thixocasting was investigated. The wear behavior of the AA7075 alloy is examined for three cases: extruded with T6 heat treatment, as-thixocast, and thixocast with T6 conditions. The dry sliding wear test was conducted with a tribometer according to ASTM G-99 standard. The microstructures were characterized by optical microscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray analysis (EDX). The tensile and hardness tests were performed to evaluate the mechanical properties. The AA7075 alloy was successfully shaped by thixocasting. The as-thixocast sample exhibited typical globular structures with multinary eutectic structures along the grain boundaries. The globular grains transform into a polygonal structure, and the grain size increases from 50 μm to 60 μm in the thixocast + T6 sample. This microstructure exhibited excellent wear resistance under dry sliding conditions in the thixocast + T6 sample. The aging treatment with prolonged solution process improved the mechanical properties two times and the wear rate three times for the thixocast AA7075 alloy. Furthermore, the thixocast + T6 sample exhibited a significant decrease in the coefficient of friction with the lowest wear rate compared to the as-thixocast sample. The dominant wear mechanisms are microdelamination, adhesion, and oxidation in all samples.

Effect of non-isothermal aging on the microstructure and properties of Al-Zn-Mg-Cu alloys

In this paper, hardness test, electrochemical corrosion test and intergranular corrosion test were used to study the mechanical properties and corrosion resistance of Al-Zn-Mg-Cu alloy after non-isothermal aging treatment with four different heating rates, and scanning electron microscope and transmission electron microscope were used to study its microstructure changes. The results show that at the heating rate of 20 ℃/h when the specimen temperature is increased from 100 ℃ to 180 ℃(20-H180), its hardness and tensile strength after quenching were enhanced to 183.1 HV and 582 MPa, much better than T6 sample. The results of electrochemical testing show that the self-corrosion current density is 0.0024 mA/cm2 and the corrosion rate is 0.0772 mm/a. The maximum depth of intergranular corrosion is 27.8 µm, which is good corrosion resistance and better than the other three heating rate samples, and comparable to corrosion resistance of T76 sample. The results of transmission electron microscopy show that the precipitated phase in the crystal is dominated by a uniform η' phase, which can improve the hardness and mechanical properties of the matrix, the grain boundary precipitated phase is discontinuous, the PFZ is obvious, and the width is 44.8 nm, improving corrosion performance of the alloy, exceeding the corrosion resistance of T76.

Effects of heat treatment on microstructure and tensile mechanical properties of isothermal die forged AZ80–Ag casing with large size

The microstructure evolution and tensile mechanical properties of the isothermal die forged AZ80–Ag casing with large size under different heat treatment conditions were investigated. The microstructure was characterized by scanning electron microscope and electron backscatter diffraction techniques, and the tensile mechanical properties were tested at room temperature, 120 and 150 °C, respectively. The results show that the area fraction of discontinuous precipitates with stronger strengthening effect is higher in T5 sample than that in T6 sample, therefore T5 sample exhibits a more pronounced precipitation hardening and the highest tensile strength at room temperature. However, as the temperature increases, the tensile strength of T5 sample decreases rapidly and is lower than that of T6 sample or even the as-forged samples at 150 °C. The reason is that discontinuous precipitates are less resistant to high temperature softening than continuous precipitates.

The use of MCDM techniques to assess fluid pressure on the bending quality of AA6063 heat-treated tubes

This paper investigates the bending of aluminum tubes under different fluid pressure and heat treatment conditions. The application of multi-criteria decision-making (MCDM) methods was evaluated for selecting the best forming condition considering cross-section ovality, thinning, and thickening of the bent tubes. Analytic hierarchy process (AHP) was used for criteria weighting, and technique for order of preference by similarity to ideal solution (TOPSIS) and multi-objective optimization on the basis of ratio analysis (MOORA) were used for alternative ranking. A combination of various types of AA6063 tubes, including as-received (R), annealed (O), and artificial aged (T6), with different fluid pressures (0, 1, 1.8, 3.2, and 3.6 MPa) were assumed to be as the alternatives (forming conditions). The results demonstrate that the ovality and thickening of the bent tubes decrease by increasing the internal fluid pressure. On the other hand, increasing the internal fluid pressure gives rise to an increase in thinning of bent tubes. The O sample has the lowest ovality and thickening while the T6 sample has the lowest thinning. MCDM analysis revealed that the O samples at higher pressures show better bendability.

The nanoscale mechanisms of strengthening and ductility enhancement in an Al–Mg–Si–Mn alloy on processing by high-pressure torsion

In this work we show that high-pressure torsion (HPT) processing of an Al-1.0at%Mg-0.8at%Si-0.2at%Mn in T6 state causes an 81% increase in ultimate tensile strength (UTS) to reach 559 MPa, whilst, remarkably, retaining a very good ductility of 14%. After an initial decrease in ductility for up to 1 HPT turn, further deformation up to 5 turns remarkably causes increases in ductility as well as increases in hardness and UTS. Analysis by X-ray diffraction line broadening and transmission electron microscopy show that during HPT processing a high density of dislocations are produced, and the grain size decreases from 3 μm for T6 sample to around 286 nm for 5r-HPT sample. Atom probe tomography reveals solute atoms strongly segregate on ultrafine-grained boundaries for a 5r-HPT sample. A model for the strengthening mechanisms is established to evaluate contribution of dislocations, grain boundaries, solid solution atoms, precipitates and solute (co-)clusters. We show that in the HPT processed 6xxx-series Al–Mg–Si alloy the strengthening caused by solute segregation at dislocations and on grain boundaries is the dominant strengthening mechanism. This work illustrates a rare case of a beneficial concomitant increase of strength and ductility during HPT. The result is an AA6xxx material with strongly increased strength and very good ductility as compared to the widely employed commercially available AA6xxx-T6 alloys.

Fracture toughness and microstructure damage behavior of thin Al–Cu alloy fabricated by wire-arc directed energy deposition

This study aimed to investigate the factors influencing the fracture toughness of thin Al–Cu alloy fabricated using Arc-Direct Energy Deposition (Arc-DED). By adjusting process parameters, samples with different microstructure characteristics were obtained, including an air-cooled (AC) deposit with a high proportion of equiaxed grains, a water-cooled (WC) deposit with a high proportion of columnar grains, and a post-heat-treated air-cooled deposit (T6) with numerous nano-sized precipitates. The conditional fracture toughness (KQ)/crack tip opening displacement (CTOD) values for the AC, WC, and T6 samples were 11.7 MPa m1/2/23.27 μm,11.4 MPa m1/2/22.70 μm, and 17.6 MPa m1/2/22.39 μm, respectively. The fracture toughness of the T6 sample was 50.4% and 54.4% higher than that of the AC and WC samples, respectively. The heterogeneity of the equiaxed/columnar microstructure affected the distribution of brittle θ-Al2Cu phases and pores, thereby influencing crack behavior. While columnar grains exhibited a stronger capacity for accumulating geometrically necessary dislocations (GNDs) and coordinating deformation compared to equiaxed grains, cracks were more likely to propagate along grain boundaries when the loading direction was parallel to the growth direction of columnar grains. Consequently, flat crack paths were observed in columnar grains, while equiaxed grains displayed tortuous paths. Furthermore, the precipitation of nano-sized θ'-Al2Cu phases contributed to improved fracture toughness. By integrating microstructure characterization, fractographic observation, analysis of uneven grain deformation behavior, and examination of GNDs distribution near crack paths, the study revealed microscopic damage characteristics, fracture behavior, and toughening mechanisms.

Impact toughness and fractography of diverse microstructure in Al-Cu alloy fabricated by arc-directed energy deposition

To investigate the effects of heterogeneous microstructure, precipitates, and pore defects on dynamic impact toughness of Al-Cu alloy fabricated by arc-directed energy deposition (Arc-DED). Samples with diverse microstructures were prepared by adjusting the forming parameters, namely air cooling (AC), water cooling (WC), and the post-treatment, hot isostatic pressing (HIP), and heat treatment (T6) samples. The impact fracture behavior of samples with Charpy V-notched was studied by an instrumented drop hammer impact testing machine which can provide a load-displacement curve. The important load parameters and the absorbed energy at different stages can be determined by the load-displacement curve. The results show that the impact absorbed energy of the AC/WC/HIP/T6 sample was 1.33 ± 0.20, 1.96 ± 0.26, 1.91 ± 0.18, and 2.54 ± 0.21 J, respectively. The impact fracture mechanism was discussed as the corresponding fractographic observations. Brittle fractures with inhomogeneous dimples were observed in all the samples. The key determinant of the impact toughness was the block-shaped brittle θ phase that precipitated along the grain boundaries and pore defects. The equiaxed/columnar heterogeneous microstructure affects not only the coordinated deformation ability of grains but also the distribution of brittle θ phases. Therefore, compared with the AC sample, the impact toughness of the WC sample with a low-volume fraction θ phase, the HIP sample with low porosity, and the T6 sample with a large amount of ductile θ″/θ' phases was significantly improved. This study provides valuable insights for improving the dynamic impact resistance of Arc-DED fabricated Al-Cu alloy.

Evaluation of Limited Sampling Strategies for Bayesian Estimation of Daptomycin Area Under the Concentration-Time Curve: A Short Communication.

Increasing evidence supports daptomycin therapeutic drug monitoring. The author's reference center used to perform therapeutic drug monitoring in patients who receive high-dose daptomycin for bone and joint infections, with a three-sample strategy to estimate the daptomycin daily area under the concentration-time curve (AUC). The objective of this study was to evaluate simpler strategies based on only 2 or 1 sample(s). The authors used the BestDose software to estimate the daptomycin AUC after Bayesian posterior estimation of individual pharmacokinetic (PK) parameters at steady state. The reference AUC (AUC full ) was based on 3 samples obtained predose (T0) and approximately 1 hour (T1) and 6 hours (T6) after the start of a 30-minute infusion of IV daptomycin. It was compared with the AUC based on all possible 2-sample and 1-sample strategies. Bias, imprecision, regression, and Bland-Altman plots were used to assess the performance of the alternative strategies. Data from 77 patients were analyzed. The mean AUC full value was 936 ± 373 mg·h/L. The best 2-sample strategy was T0 + T6, with a mean prediction bias of 0.13 mg·h/L and absolute imprecision of 3%. The T0 + T1 strategy also performed well with a mean bias of -10 mg·h/L and imprecision of 3%. The best 1-sample strategy was the T6 sample only with a bias of 2.19 mg·h/L and imprecision of 6%. Bayesian estimation of daptomycin AUC based on a two-sample strategy was associated with negligible bias and imprecision compared with the author's usual three-sample strategy. The trough and peak strategy may shorten and simplify patient visits and reduce assay labor and costs.

Effect of ageing treatment process on the microstructure development and mechanical properties of 6082 Al alloy

Different ageing treatment process was conducted to improve the mechanical properties of 6082 Al alloy. Tensile results show that as compared to the T6 sample, the ultimate tensile strength, yield strength and elongation of the T6I6 sample increase by 3.2 %, 3.5 %, and 47.3 %, respectively, the ultimate tensile strength, yield strength and elongation of the RD+T6I6 sample increase by 12.9 %, 11.8 % and 12.5 %, respectively. Microstructural results reveal that holding at 65 ºC for 336 h after pre-ageing promotes the formation of GP zones and stimulates the transformation of GP zones into β" precipitates during subsequent ageing at higher temperature. The introducing of the asymmetric rolling deformation after pre-ageing can reduce the average grain size, induce high-density dislocations and increase the average Taylor factor (M) due to the increasing of S and Brass texture. The dislocations have a good effect on the formation of fine β" precipitates during subsequent ageing. This microstructure is responsible for the improvement of the mechanical properties.

A combination of modified atmosphere packaging and two chemical disinfectants: Effects on microbial, sensory, and physicochemical properties of raw ready-to-eat leek.

In the present study, the effect of modified atmosphere packaging (MAP) on microbial (total aerobic count, yeasts and molds, Enterobacteriaceae, psychrotrophic bacteria, and lactic acid bacteria), physicochemical (pH, moisture content, and color), and sensory properties of raw ready-to-eat leek was investigated after disinfection using Percidin-Nanosil disinfectants. There were six different treatments, of which four samples were packaged as MAP (T1 to T4) and two samples were packaged as non-MAP (T5 and T6). The highest and the lowest reduction in the number of microorganisms after disinfection was observed in psychrotrophic bacteria and total aerobic count, respectively. The count of microbial variables in T2 sample (87% N2, 3% CO2, and 10% O2) was lower than in other treatments. No significant difference was observed in the physcochemical properties (moisture and pH) of treated samples except for the color of T6 sample (cling film) compared to other treatments (p< .05). It is noteworthy that the panelists did not recognize differences among T1, T2, and T5 samples. However, T2 treatment was effective in maintaining microbial, physicochemical, and sensory properties of leek compared to the other treatments. Also, T6 sample showed the lowest quality in all parameters. Disinfection combined with MAP was able to maintain the physicochemical, microbial, and sensory properties of raw ready-to-eat leek during storage.

Microstructural and Mechanical Properties of a Heat-Treated EV31A Magnesium Alloy Fabricated Using the Stir-Casting Process

This study aims to prepare a stir-cast EV31A magnesium alloy and investigate the effects of the T4 condition (solid solution strengthening) and T6 condition (solid solution strengthening cum age hardening) on the phases, microstructure, mechanical properties, and fractography. The solid solution at 520 °C for 8 h allows the Rare-Earth Elements (REE) to dissolve in the Mg matrix, but the solubility is limited by the presence of Zn. This phenomenon is responsible for the T4 heat-treated alloy’s strengthening, which raises the UTS to 212 MPa. The formation of new grains within the grains causes an increase in grain boundaries and dislocations during the T6 heat treatment process, increasing the strength (UTS) of the EV31A alloy to 230 MPa. In all three test conditions, the fractography of tensile samples revealed a cleavage-ductile/mixed mode fracture. As expected, the fine-grained T6 sample exhibited superior strengthening at the expense of ductility.

Precipitation phenomena and strengthening mechanism of Al–Cu alloys deposited by in-situ rolled wire-arc additive manufacturing

We reported the precipitation phenomena and strengthening mechanism of Al–Cu alloys deposited by in-situ rolled wire-arc additive manufacture (WAAM) technology. The results indicated that in-situ rolling was able to eliminate most of the solidification shrinkage cavities during deposition, however, high density of fine hydrogen pores formed after T6 heat treatment, which was caused by hydrogen micropore precipitation. A slight coarsening of the pre-existed pores was mainly controlled by coalescence of micropores or Ostwald ripening. Most of the eutectic structure with continuous or semi-continuous distribution in grain boundaries dissolve into the matrix during T6. Some undissolved θ and high density of needle-like θ′ precipitates could be observed in grain interior. The UTS and YS of the alloy reached 454.4 ± 23.8 MPa and 356.6 ± 17.1 MPa after T6 treatment, which was mainly due to the precipitation strengthening. The initiation and propagation of the cracks may be ascribed to the existence of pores for the as-deposited and T6 sample. The representative transgranular fracture could be observed in T6 sample while the crack prefers to propagate along the eutectic structure with continuous distribution in grain boundaries of as-deposited sample.

Accelerated solid solution and aging induced by electropulsing in Mg-Al-Ca-Mn alloy

The effects of electropulsing treatment (EPT) and conventional heat treatment on the microstructure and mechanical properties of extruded Mg-1.18Al-0.3Ca-0.46Mn alloy were investigated.The results showed that EPT can replace the solid solution treatment, refine the grains and reduce 33% of the followed peak aging time (compared with the T6 sample). The mechanism of accelerated aging process may mainly base on the fact that EPT induce more vacancies and dislocations, which makes it easier to nucleate than traditional solid solution treatment. This interesting result exhibits a new pathway to strengthen Mg alloys in a very short time.

Effect of retrogression re‐aging treatment on the stress corrosion behavior of the 7075 Al–Zn–Mg–Cu alloy

AbstractThis paper studies the influence of the regression re‐aging (RRA) process on the mechanical properties and corrosion resistance of 7075. In the RRA heat treatment, the material properties are markedly affected by the variation of parameters in the regression stage. When the regression temperature and the regression duration increase, the mechanical properties of the material decrease. There was no intergranular corrosion in the samples treated by RRA, while obvious intergranular corrosion occurred in the T6 sample. Compared with the T6 sample, the RRA‐190‐0.5 sample with optimized parameters has a higher density of the precipitated phase and narrower precipitate‐free zone, and the precipitated phase along the grain boundary is discontinuous, isolated, and short. Compared with the single‐stage peak aging treatment, the RRA treatment can considerably improve the corrosion resistance and stress corrosion resistance but slightly reduce the strength. The best heat treatment process condition is 120°C/24 h + 190°C/0.5 h + 120°C/24 h.

Effect of heat treatment on the microstructure and mechanical properties of a multidirectionally forged Mg-Gd-Y-Zn-Zr-Ag alloy

Multidirectional forging (MDF) was successfully applied to fabricate large-size Mg-Gd-Y-Zn-Zr-Ag alloy in this work and effects of T4, T5 and T6 treatments on the microstructure and mechanical properties of the as-forged alloy were analyzed. Results show that dynamic recrystallization (DRX) occurs and second phase particles precipitate along the grain boundary during the MDF process. After annealing treatment (T4), the volume fraction and size of dynamic precipitates slightly increase at a lower temperature (430 °C) compared with those of MDFed sample, while they are dissolved into the α-Mg matrix at a higher temperature (450 °C). At the meantime, short plate-shaped long-period stacking ordered (LPSO) phases are observed in the DRX grains of the MDFed sample and then dissolved into the α-Mg matrix during annealing at both temperatures. Typical basal texture is identified in the MDFed sample, but the basal pole tilts away from final forging direction and rare-earth texture component with <112¯1> orientation parallel to penultimate forging direction becomes visible after annealing. The T6 sample annealing at 430 °C for 4 h and ageing at 200 °C for 34 h exhibits the superior strength and ductility in this study. The ultimate tensile strength, tensile yield strength and elongation to failure, which is 455 MPa, 308 MPa and 7.7%, respectively, are overall improved compared with the directly-aged (T5) sample. This paper provides a superior heat treatment schedule to manufacture high-performance large-scale Mg-Gd-Y-Zn-Zr-Ag components for industrial production.

Mechanism of microstructure and texture evolution during shear loading of AA6063 alloys

The cyclic shear test of 6063 aluminum alloys under T4 and T6 conditions was carried out at room temperature. The microstructure and texture evolution were investigated using electron backscattered diffraction (EBSD) at several instances during cyclic shear deformation. Hardly any change in grain size was observed during the cyclic shear test of T4 and T6 samples. The local residual strain distribution measured in the form of average kernel misorientations (KAM) values increases continuously with an increase in shear strain for both samples. The increase in KAM value was higher for the T6 sample compared to the T4 sample during forward (F) shearing. On reversing the loading path, the increase in KAM value was higher for forward + reverse (FR) and forward + reverse + forward (FRF) straining of the T4 sample compared to the T6 sample. The cube texture was found to be unstable during shear deformation. A significant rotation of texture was observed in both T4 and T6 samples. However, the extent of rotation was slightly greater for the T6 sample as compared to the T4 sample. It was observed that the latent hardening of (1-11)<101>was more than (111)<1-01>in the T4 sample. Similarly, the latent hardening of (1-1-1)<011>was more than the (111)<1-01>in the T6 sample. The origin of latent hardening was attributed to the formation of sessile jogs during dislocation-dislocation interactions on different planes of T4 samples and the difference in volume fraction of precipitates on different planes of T6 samples. The mechanical properties show that the 0.2% YS increases with subsequent reverse and forward shearing for the T4 sample. However, the 0.2% YS during subsequent reverse shearing is lower than the initial forward shearing for the T6 sample. This decrease in yield stress upon loading reversal is attributed to the presence of deformation-induced intragranular back stresses within the T6 material. It is observed that the rate of cross slip of dislocations depends on the athermal dislocation content, presence of dislocation debris in the unfavorable grains, and the difference in the latent hardening values of different slip systems for the T4 and T6 materials.

Effect of Physico-Chemical Characteristics of Developed Mixed Fruits Wine during Fermentation Process

The mixture of fruits pulp containing low sugar and thus sugar level was adjust from 25 oBrix by using sugar solution. The pH level of mixture was adjusted at 4. The juice was yeast by Saccharomyces cerevisiae with 1%. The Specific gravity of mixed fruit wine showed an increasing trend for all the treatments with fermentation period up to 0, 10, 20 and 30 days. The TSS largely affects the various physic-chemical parameters of fermented wine. Sugar is the main substrate for fermentation of fruits juice into alcohol. The specific gravity of the wine was found to be decreased with increase in sugar percent. The highest value of alcohol content was found 17.43% (v/v) in T6 sample after last day of fermentation period with 1% of yeast concentration. It has been observed that the sample show the high alcoholic wine.

Effects of precipitate on the slip activity and plastic heterogeneity of Mg-11Y-5Gd-2Zn-0.5Zr (wt. %) during room temperature compression

To understand the effects of precipitate on the deformation mechanisms and plastic heterogeneity of a cast Mg–11Y-5Gd-2Zn-0.5Zr (wt.%) alloy, quantitative comparison studies were performed on the solid solution (T4) and peak-aged (T6) samples during room temperature compression based on slip trace analysis and electron backscatter diffraction (EBSD) analysis. At 10% plastic strain: no twins were observed in both T4 and T6 samples; the dominant slip mode transitioned from 2 nd order pyramidal <c+a> slip (34.1%) to basal <a> slip (50.5%) after the T6 treatment, which indicated that the precipitate-hardening effect for pyramidal slip was stronger than that for basal slip. Substantial active slip systems (up to 40%) exhibited low normalized Schmid factors (<0.1), implying that local stress deviated from the globally applied stress. Compared to the T4 sample, a larger magnitude of geometrically necessary dislocation (GND) density was found in the T6 sample, which indicated that the precipitates enhanced the plastic heterogeneity in terms of GND density. Most of the high GND density areas were near grain boundaries (GBs), but they also appeared in grain interiors. Almost every near-GB area with larger GND density tended to follow the conditions: (1) large orientation discrepancy between neighborhood grains; (2) at least one grain exhibiting slip traces; (3) the GB with the X phase. The GBs where slip transfer occurs tended to exhibit a homogeneous GND density distribution.

Bonding and microstructure evolution in electromagnetic pulse welding of hardenable Al alloys

Electromagnetic pulse welding (EMPW) is a promising solid-state joining process, offering fast and strong bonding with no heat affected zone. Despite the growing interest in this process, there is little understanding of the dynamic phenomena that lead to bonding and microstructural changes during EMPW of key engineering materials such as age-hardenable aluminium alloys. This study combines experiments with numerical modelling of plastic deformation to provide an insight to these phenomena in joining of a high-strength aluminium alloy in the T4 and T6 temper conditions. Initially, bonding criteria are postulated in view of the calculated plastic strain at the interface of the T4 sample. These criteria are then used for the prediction of the extent of bonded interfaces for different sets of materials and process parameters. The predictions are shown to be in quantitative agreement with the experimental results for the T6 sample. The corresponding microstructural studies show that bonding is associated with remarkable microstructural changes in the samples, including dissolution of precipitates, formation of high-angle boundaries, and recrystallisation, especially near the bonded interfaces. Moreover, the results of post-weld heat treatments and mechanical testing demonstrate that the impact-induced deformation in EMPW can also influence subsequent precipitations, hence result in improved properties of the entire sample, in a way not achievable by conventional age hardening treatments.