Secondary Hardening Research Articles

Electrochemical Properties of Diluted Al-Mg Alloys With Columnar-To-Equiaxed Transition

The objective of the present research is to study the corrosion susceptibility of two Al-Mg diluted alloys (Al-0.5wt.%Mg and Al-2wt.%Mg) with different grains structures obtained by directional solidification (columnar, equiaxed and columnar-to-equiaxed transition, CET) in 0.5% NaCl solution, at room temperature. The corrosion resistance is analyzed by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques in both longitudinal and transversal sections of the samples. The columnar grain zone presents higher corrosion resistance than the equiaxed grain zone. In addition, the transversal section shows higher corrosion resistance than the longitudinal section of the samples. Then, the Al-0.5wt.% Mg alloy displays higher corrosion resistance than the Al-2wt.% Mg alloy. The values of the polarization resistance are used as a basic criterion for the evaluation of the corrosion resistance of both alloys. In this way, when the polarization resistance decreases with the increasing in the distance from the base, the grain size, secondary dendritic arm spacings and hardness increases. In addition, when the polarization resistance increases, the critical temperature gradient decreases.

Hydrogen Trapping States and Apparent Hydrogen Diffusion in Laser Additively Manufactured Ultra-High Strength AerMet100 Steel as a Function of Secondary Hardening

Microstructures, reversible hydrogen trapping states, and effective hydrogen diffusion coefficients (DH,eff) of laser additively manufactured (LAM) ultra-high-strength AerMet100 steel in tempered conditions were studied by several material characterization methods, to determine diffusible, trapped, and total hydrogen content. With secondary hardening temperatures in the range of 454°C to 566°C, increasing temperature mainly promotes M2C carbide coarsening and film-like reverted austenite thickening in the steel. Reversible hydrogen traps of tempered LAM AerMet100 steel are closely related to the precipitation behavior of highly coherent M2C carbides. The desorption activation energy of the reversible hydrogen traps in the steel is seen to increase from 17.9±0.3 kJ/mol to 21.8±1.3 kJ/mol with temperature increasing from 454°C to 566°C. This correlates with the composition and size change of M2C carbides at a higher tempering temperature. Hydrogen trapping capability of the steel has a peak value at a tempering temperature of 482°C corresponding to the combination of both high amount and medium trapping intensity of these reversible hydrogen traps. This results in the lowest diffusible and highest total hydrogen concentration for precharged H specimens of the steel. In addition, the DH,eff of LAM AerMet100 steel in the overaged condition is not only influenced by the increased thickness of film-like reverted austenite but also simultaneously affected by the altered density of M2C carbides. In comparison with the lowest DH,eff (approximately 2.4 × 10−9 cm2/s) of LAM AerMet100 steel tempered at 482°C, a slightly higher DH,eff of the steel tempered at a higher temperature is achieved by the apparent decrease of reversible hydrogen traps due to a decrease in density of the highly coherent M2C carbides. These findings are important when considering achieving improved hydrogen embrittlement resistance for LAM high Co-Ni secondary hardening ultra-high-strength steel in an over-aged condition at the strength level of interest.

Comprehensive analysis of nitriding behavior and synergistic strengthening mechanism on quenched M50 steel

M50 secondary hardening steel is widely used as high-end bearing steel for engine shafts in the aerospace industry. In this study, plasma nitriding at different temperatures varying from 410 to 570 °C was performed on quenched M50 steel to investigate the response of the microstructure and mechanical properties to nitriding temperature and advance the scientific understanding of the mechanism involved. The nitrided samples were fully characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, electron microprobe analysis, Vickers hardness tester, and Pin-on-disc tribometer. The results revealed that the nitrided layer's thickness, microstructure, hardness, and wear resistance depended on the treatment temperature. When the nitriding treatment performs at secondary-hardening temperature, the samples were endowed with excellent wear resistance and gentle hardness profile, i.e., hardness profile with a gradually reducing hardness profile towards the core, attributed to the synergistic strengthening. Moreover, the thermodynamic calculation was involved to clarify the formation mechanism of coarse intergranular precipitation, which can be connected to form a wave shape line at higher temperatures.

Thermally activated dependence of fatigue behaviour of CrMnFeCoNi high entropy alloy fabricated by laser powder-bed fusion

The CrMnFeCoNi high-entropy alloy demonstrates a promising potential for applications over a range of temperature. The alloy also shows excellent printability to be fabricated by additive manufacturing for complex structures. Nevertheless, there are limited studies on the thermo-mechanical behaviour of the alloy, in particular when fabricated by laser powder-bed fusion. This study provides an in-depth understanding of the relationship between as-built cellular microstructures and fatigue behaviour at a range of temperatures (22–600 °C) in particular concerning the stability of dislocation cells and thermo-mechanical dependence of the fatigue behaviour of the alloy. At all tested temperatures, the alloy exhibits a very short duration cyclic hardening with a low hardening rate followed by a cyclic softening. The high density of dislocations already existing in as-built condition were able to accommodate most of the prescribed strain. Hence, only a small number of mobile dislocations needs to be generated, causing a short cyclic hardening phase. Upon further loading, the back stress associated with the long-range stress field was dominant factor governing the cyclic softening behaviour. The similitude relationship provided insights into the stability of as-built cells, in particular it explains why the size of as-built cells did not change during cyclic loading at 22 °C. The significant reduction in dislocation density due to the increased annihilation rate and untanglement of dislocation substructures thanks mainly to thermal assistance at elevated temperatures led to a decrease in cyclic strength and related properties (yield stress, friction and back stress, hysteresis loop shape parameter and energy per cycle). The LPBF HEA shows an insignificant strain rate dependence of the primary cyclic hardening and softening in the range of 10 −3 s −1 and 10 −2 s −1 . However, the dynamic strain ageing results in a secondary cyclic hardening at 400 °C and the reversed strain sensitivity at temperatures from 200° to 400 °C. The fracture mode was transgranular at 22–400 °C but changed to more intergranular-like at 600 °C due to the decohesion of grain boundaries, resulting in a reduction in fatigue life.

Methods for Characterising the Precipitation of Nanometer-Sized Secondary Hardening Carbides and Related Effects in Tool Steels

AbstractNanometer-sized secondary hardening carbides are the most relevant microstructural constituents regarding the properties of tool steels. Due to their extreme fineness, direct inspection by microscopy is difficult and time consuming despite the progress recently achieved, e. g. by energy filtering transmission electron microscopy. Indirect methods are therefore additionally employed to obtain more detailed information on the processes taking place. Differential scanning calorimetry and in-situ hot hardness testing are demonstrated as powerful methods for the determination of kinetic data. In combination with results from a recently developed tensile specimen and test procedure for hard materials with low ductility, more detailed conclusions can be drawn on the effects of secondary hardening carbides on the strength and the thermal stability.

Effect of friction stir welding tool hardness on wear behaviour in friction stir welding of AA-6060 T66

Friction stir welding is a solid-state joining process with a wide range of industrial applications in the e-mobility, automotive, aerospace and energy industries. However, friction stir welding is subjected to process-specific challenges, including comparatively high process forces and friction stir welding tool wear resulting from tribological interaction between the tool and workpiece. The geometric-related friction stir welding tool wear can cause varying material flow conditions, lateral path deviations and premature tool failure, with detrimental economic and technological consequences. This study systematically analyses the wear behaviour of friction stir welding tools as a function of tool hardness. To compare and differentiate the geometric-related tool wear as a function of tool hardness, experiments were carried out with a hardness of 240 HV, 410 HV and 580 HV. Whereas 240 HV is non-hardened, 410 HV is 50% of the secondary hardness maximum and 580 HV is the secondary hardness maximum of the tools made of H13 tool steel (hot-working steel, X40CrMoV5-1). During the experimental tests, the shoulder and probe exhibited varying wear and geometrical deviations. The investigations were carried out with a force-controlled robotized welding setup in which AA-6060 T66 sheets with a thickness of 8 mm were joined by weld seams up to a total length of 80 m.

Microstructure and mechanical properties of Si-rich H13 steel processed via austempering and tempering

Nanobainite shows high tempering stability. However, studies of the multi-tempering behavior of nanobainite hot-working die steel are rare. In the present work, the microstructure and mechanical properties of Si–H13 nanobainite steel, subjected to multi-tempering processes, have been investigated via microstructural characterization and mechanical tests. The results show that the filmy retained austenite decomposed into ferrite and granular V2C during the first tempering process. The size of V2C increased slightly after the second tempering. VC precipitated from bainitic ferrite of the third tempered sample. Because of hindering effects that decomposition products of filmy retained austenite have on the combination of bainitic ferrite laths, the increment of thickness of bainitic ferrite lath is only 29% (26 nm) after multi-tempering processes. The yield strength of multi-tempered samples is obviously higher (by more than 50%) than that of austempered samples. With an increase in number of tempering, the dominant strengthening contribution changes from grain boundary strengthening and dislocation strengthening to precipitation strengthening. Moreover, the precipitation of carbides results in secondary hardening during the tempering process. Although the thickness of bainitic ferrite lath became coarse, the hardness of the multi-tempered sample was approximately the same as that of austempered sample. Hence, the Si–H13 nanobainite steel exhibits good tempering stability.

Структура и механические свойства алюминиевого сплава АК12Д, подвергнутого обработке трением с перемешиванием

The application of friction stir processing (FSP) to modify the structure of the Al–Si alloys, in particular the fragmentation of large silicon particles, can lead to an increase in the level of mechanical properties. This work is aimed to study features of local surface hardening of AK12D aluminum alloy (Al–Si–Cu–Ni–Mg system) during FSP and subsequent T6 hardening heat treatment. The authors investigated the influence of FSP and subsequent heat treatment parameters on the structure, microhardness, and hardness of the AK12D alloy. FSP was carried out at speeds of processing tool rotation and traverse of 2000 rpm and 8, 16 mm/min, respectively. The subsequent hardening T6 heat treatment was carried out according to the standard regime for the AK12D alloy. The paper shows that the FSP mode at a rotation speed of 2000 rpm and a traverse speed of 8 mm/min contributed to the formation of a monolithic and defect-free treatment zone. The study revealed that the formed microstructure is heterogeneous due to the influence of various thermomechanical effects. The most intense structural changes occurred in the stir zone. Friction stir processing and subsequent heat treatment led to fragmentation and partial dissolution of intermetallide particles in the α-Al solid solution followed by its decomposition and formation of secondary hardening phases. Moreover, the FSP and T6 heat treatment led to the formation of quasi-equiaxed fine-grained structure. The AK12D alloy microhardness after treatment under the study varied nonmonotonically and depended on the structure in different zones. At the same time, the Brinell hardness values after FSP and subsequent T6 heat treatment increased compared to the initial heat-treated state.

Microstructure and Mechanical Properties of Microalloyed Steels Containing Molybdenum

Microalloyed steels have a maximum of 2% in alloying elements and are used in the automotive and petrochemical industries. The microstructure and mechanical properties of these steels depend on chemical composition, processing and addition of molybdenum, niobium, titanium and vanadium. To evaluate the molybdenum effect in microstructure and mechanical properties, two microalloyed steels, with similar levels of niobium, titanium and vanadium, were prepared and forged. The steels have 0.056 and 0.160 percent by weight of molybdenum. The bars were homogenized, quenched and tempered. The specimens were machined for tensile and impact tests, hardness and microstructural analyzes by confocal and scanning electron microscopy. The ThermoCalc software was used to evaluate the carbides characteristics. The results show that steel with 0.160% Mo presents greater amount of bainite and austenite retained. It’s possible that formation of carbides by the secondary hardening mechanism increase in mechanical strength and a reduction in toughness.

Secondary Hardening of High-N Ni-Free Stainless Steel

Secondary Hardening of High-N Ni-Free Stainless Steel

Effect of Secondary Aging of AA7075 Aluminum Alloy to Hardness

In this study, one of the major aluminum alloys AA7075 was held to obtain the maximum benefit for structural parts. Nowadays for the energy efficiency of vehicles like electric cars or aerospace vehicles weight reducing efforts are needed. To obtain lighter structures specific strengths are gaining importance. In our study, AA 7075 aluminum alloy was processed with additional heat treatment rather than T6 condition to obtain high strength. According to our previous studies, statistical methods seemed very useful to predict probable strength very precisely, for this reason, Box-Behnken Surface Response Method was used. By applying statistical methods, the artificial aging temperature and time were optimized. According to optimized temperature and time, the secondary aging heat treatment was done. In this study three T6 conditions 150, 200, and 250 oC with four treatment times, 1,2,4 and 6 hours were chosen and applied. The secondary aging temperature and time were obtained from Box-Behnken optimization study results and found as 182 oC and 2 hours were applied to all samples. As a result, after secondary aging heat treatment maximum hardness of 151 Hv was obtained from samples that aged at 150 oC, and 250 °C for 1 hour, which is almost doubled because the T6 aged sample has a hardness value of 86 Hv. This is obvious that the strength almost doubled, therefore it is possible to use sections almost half of the T6 condition samples.

Influence of aluminium and niobium alloying on phase composition, structure and properties of heat- and wear-resistant cast iron of Cr-Mn-Ni-Ti system

The paper presents the data on phase composition and structure forming for the alloys and oxide layers, on distribution of elements among the alloy structural components and oxidation surface through the depth of oxide and sub-oxide layers, on variation of wear resistance, scale resistance, growing stability and mechanical properties of cast iron of Cr-Mn-Ni-Ti-Al-Nb system depending on different aluminium and niobium content and thermal accumulating capacity of a casting mould. Complex carbides (Nb, Ti)C are forming in white cast iron during niobium alloying. Quantitative metallographic analysis of (Nb, Ti)C carbides and (Cr, Fe, Mn)7C3 complex carbides was carried out on the samples with examined composition. The tests for scale resistance were conducted, structure and properties of cast iron were investigated. It was determined that chemical composition and structure of oxide layers depend on distribution of alloying elements among the alloy structural components. It was established that the areas of oxide film surface layer, which were formed on eutectics, contain mainly manganese; its concentration is more than 65 %, while Al is 4 % and Cr is 1 %. Manganese leads to increase of defects amount, such as pores, micro-cracks and vacancies, in oxide film during high-temperature gas oxidation; penetration ability of this film also increases, what has a negative effect on metal resistance to further destruction caused by oxidation. The film becomes porous, its thickness enlarges. Aluminium provides favourable influence on forming of the thin protective spinel-type films (dense substance with good metal adhesion) with minimal amount of defects; diffusion through such oxide film is very difficult. The areas of oxide layer, which were formed on austenite dendrites, contain mainly aluminium; its concentration is more than 24 %, while Mn is 16 % and Cr is 12 %. High aluminium content provides small film thickness. Joint alloying by aluminium and niobium leads to simultaneous increase of heat resistance and wear resistance. Wear resistance increased as a result of enlargement of the part of primary carbides (Nb, Ti)C with high hardness in the structure of cast iron. Composition of oxide films includes aluminium which strengthens their protective properties and rises of the alloy scale resistance. Alloying by niobium leads to secondary hardening during cooling in a casting mould. Dispersion particles of М7С3 carbides are forming in solid state, thereby no structure degradation occurs during testing at increased temperatures, and growing stability rises.

Effect of structure and phase content on wear resistance of the economical alloyed metastable and secondary hardening steels of Cr-Mn-Ti system

Despite a large number of studies in the field of assessing the causes of the formation of hot and cold cracks during surfacing of wear-resistant alloys, today the issues of working out the use of economically alloyed wear-resistant materials and the technique of their surfacing remain relevant. Goal: The purpose of this work is to study the effect of the structure and phase composition on the wear resistance of economically alloyed metastable and secondary hardening steels of the Cr-Mn-Ti system, as well as with additional alloying with Mo, B, V. Mechanized surfacing was carried out with flux cored wires AN-22 and AN-20 with the supply of a de-energized additive to the head of the weld pool, which reduces the content of sulfur and phosphorus, the specific consumption of electricity and increases the assimilation of alloying elements and the relative mass of the flux. Cladding by manual arc welding was carried out with coated electrodes with the addition of a depleted CaF2-coated flux-cored wire filler. When surfacing with a de-energized additive, the ratio of the filler to the main electrode, the relative mass was determined by β = m1 / m2 (m1, m2 are the mass of the filler and the electrode rod, respectively). Submerged arc surfacing was carried out in the following modes: IN = 300 ... 350 A, UD = 26 ... 30 V, q = 6 ... 10 kJ / cm, with manual surfacing - IN = 180 ... 220 A, UD = 25 ... Results: The studies carried out confirm the possibility of the formation of a “white band” both in alloys with a high concentration of austenitizing elements (Mn, C, Ni) and when alloying carbide-forming elements with a relatively low affinity for carbon (V, Mo). The indicators of resistance to cracking (КС, j-integral, δС), and, consequently, resistance to wear of secondary hardening steels are higher than those of metastable and tool steels.

Grain-size-dependent microstructure effects on cyclic deformation mechanisms in CoCrFeMnNi high-entropy-alloys

The effect of grain size on strain-controlled low-cycle fatigue (LCF) properties in the CoCrFeMnNi high-entropy alloys (HEAs) was investigated towards the distinct microstructural developments during cyclic loading at a strain amplitude of ± 1.0%. A much more prominent secondary cyclic hardening (SCH) behavior at the final deformation stage was observed in the fine-grained (FG, 18 µm) than in the coarse-grained (CG, 184 µm) CoCrFeMnNi. In-situ neutron-diffraction and microscopic examination, strongly corroborated by molecular dynamic (MD) simulations, indicated that dislocation activities from planar slip to wavy slip-driven subgrain structures within the grains acted as the primary cyclic-deformation behaviors in the FG CoCrFeMnNi. Differently observed in the cyclic behavior of the CG CoCrFeMnNi was due to a transition from the planar dislocation slip to twinning. Our findings suggested that the fatigue-resistant HEAs can be designed via tuning the microstructure with an optimal range of grain size at a specific strain amplitude.

A Comparison of Amplitude-and Time-Dependent Cyclic Deformation Behavior for Fully-Austenite Stainless Steel 316L and Duplex Stainless Steel 2205.

Austenite and duplex stainless steels are widely used in engineering, and the latter exhibits a more excellent combination of mechanical properties and corrosion resistance due to the coexistence of austenite and ferrite and higher nitrogen. However, fatigue failure still threatens their structural integrity. A comprehensive comparison of their cyclic deformation behavior is a major foundation to understand the role of duplex-phase microstructure and nitrogen in the safety assessment of engineering components. Thus, in this paper, the cyclic deformation behavior of fully-austenitic stainless steel 316L and duplex stainless steel 2205 was studied by a series of low cycle fatigue tests with various strain amplitudes, loading rates and tensile holding. A theoretical mechanism diagram of the interaction between nitrogen and dislocation movements during cyclic loads was proposed. Results show that the cyclic stress response of 2205 was the primary cyclic hardening, followed by a long-term cyclic softening regardless of strain amplitudes and rates, while an additional secondary hardening was observed for 316L at greater strain amplitudes. Cyclic softening of 2205 was restrained under slower strain rates or tensile holding due to the interaction between nitrogen and dislocations. The cyclic plasticity of 2205 started within the austenite, and gradually translated into the ferrite with the elevation of the cyclic amplitude, which lead to a decreased hardening ratio with the increase in amplitude and a shorter fatigue life for a given smaller plastic strain amplitude.

Effect of tempering temperature on impact energy of AISI 410 martensitic stainless steel at low temperatures

Abstract AISI 410 martensitic stainless-steel specimens were austenitized at 1253 K then oil quenched and tempered at 573, 673, 773 and 923 K for 3600 s. The impact energy of the specimens was tested at 298, 253, 223, 213 K and measured using ASTM E23 standard. After austenitizing and tempering, the microstructure of the specimens showed carbide precipitation. Tempering at 773 K resulted in the highest hardness due to secondary hardening, while tempering at 923 K resulted in the lowest hardness due to brittle carbide precipitation at the grain boundary which caused softening of the matrix by decreasing the solute carbon content. By contrast, the change in impact energy is inversely proportional to the hardness values. The impact surface of specimens tempered at 573, 673 and 773 K revealed transgranular fracture; on the other hand, the impact surface of the specimen tempered at 923 K revealed intergranular fracture. From our experimental results, the appropriate hardening and tempering procedure of AISI 410 for low temperatures applications is selectable.

Microstructure and Properties of Two Cr8 Cold Working Die Steel

In this paper, we studied the effect on microstructure and properties during low tempering and high tempering temperature of HNC53 and KD11max Cr8 cold working die steel by means of hardness tester, universal tensile testing machine, pendulum impact tester, metallographic microscope, SEM and EDS. The results showed that the microstructure of the two materials were spheroidized pearlite and large eutectic carbide. After quenching then tempering at high temperature 520°C and low temperature 200°C, the microstructure was martensite, eutectic carbide with large particles and small secondary precipitated carbide which was M7C3 type carbide. When KD11max was tempered at high temperature of 520°C, more nano-level secondary carbonization precipitated, and secondary hardening phenomenon was more obvious. The increase of Si and decrease of C could promote secondary hardening and improve the impact toughness of materials. KD11max impact toughness was better than HNC53.

Effect of solution annealing on low cycle fatigue of 304L stainless steel

The present study investigates low cycle fatigue behaviour of the metastable austenitic 304L steel in two variants: i) as-received and ii) after additional solution annealing at 1050 °C/30 min. The applied heat treatment resulted in a decrease of δ-ferrite volume fraction and slight grain coarsening. After the solution annealing, significantly prolonged fatigue life within the whole range of studied total strain amplitudes was observed. Such improvement is attributed to the larger grain size possessing better ductility and enhanced formation of deformation-induced martensite. The phase transformation led to a significant secondary cyclic hardening stage at high strain amplitude loading. The low cycle fatigue behaviour and principal fatigue life stages were characterized by the analysis of cyclic response. A vital supplementary data were obtained by the analysis of hysteresis loop shape carried out, for the first time on a phase-transforming material, by the generalized statistical theory. The analysis was able to follow the evolution of cyclic stress sources during the fatigue life, especially the increasing contribution of deformation-induced martensite. The identified features of cyclic plasticity were supported by electron channeling contrast imaging observations. Furthermore, electron backscatter diffraction revealed a distinct preferential localization of α'-martensite into macrobands parallel to rolling direction. Energy dispersive spectroscopy mapping identified pronounced chemical segregation of Cr and Ni which correlated well with the observed macrobands. These compositional fluctuations led to local austenite metastability which is enhanced further by the applied solution annealing.

Correlation between microstructure evolution and mechanical response in a moderately low stacking-fault-energy austenitic Fe–Mn–Si–Al alloy during low-cycle fatigue deformation

Through in-depth microstructural and mechanical characterization, a mechanism for low-cycle fatigue (LCF) deformation of an Fe-30.7Mn-4.3Si-1.8Al (in wt%) austenitic transformation-induced-plasticity (TRIP) steel at a total strain range of 2% was investigated. The LCF deformation of the steel was performed through two main deformation modes which were planar slip of Shockley partials, and ε-martensitic transformation and its reverse transformation. The varying significance of each deformation mode as well as the relevance between the two modes determined the microstructures evolved during fatigue deformation and resulted in a four-stage cyclic hardening behavior. With increasing fatigue cycles, the LCF deformation was dominated sequentially by the multiplication of partial dislocations, development of slip bands, reversible ε-martensitic transformation, and formation of more thick and crossed ε-martensite along with enhancement of planar dislocation slip, thus generating the characteristic deformation stages of primary cyclic hardening, cyclic softening, cyclic saturation, and secondary cyclic hardening correspondingly. In general, the superior LCF resistance of the steel was attributed to appreciably high plasticity reversibility during the entire fatigue deformation which was caused by reversible planar dislocation slip and ε-martensitic transformation.

Low cycle fatigue of additively manufactured thin-walled stainless steel 316L

To ensure the robust design freedom of metallic additive manufacturing, the fatigue properties and the dimensional limitation of as-built components by laser powder bed fusion (PBF-LB) are investigated. Fully reversed and strain-controlled fatigue tests were carried out on tubular specimens with different wall thicknesses, 1 mm and 2 mm, for the purpose of studying the thin-wall effect without having risk of buckling problem during compression. Two wrought conditions are also enclosed as a comparison, which are the cold worked (CW) and solution annealed condition (SA). In the as-built PBF-LB tubular specimens, deformed microstructure and deformation twins are discovered close to the surface region, together with a higher roughness of the inner surface due to the heat accumulation. The surface roughness is evaluated as micro-notches, and a higher fatigue notch factor, Kf, at lower applied strain range is revealed. The factors influencing Kf include, the non-conductive inclusions serving as crack initiation sites at the surface region, and the deformation twins formed by the local stress concentration. The strain-life of PBF-LB samples is comparable with the wrought samples. However, the fatigue strength of the responding mid-life stress shows greater difference and is in the following order, CW wrought > PBF-LB > SA wrought. Secondary cyclic hardening owing to deformation induced martensitic transformation is found in both of the wrought samples. Yet, only cyclic softening exhibits in the PBF-LB samples, which is the result of the suppressed martensitic transformation and the dislocation unpinning from the cell boundaries.