Prior Particle Boundaries Research Articles

Structural evolution and mechanical properties of 9Cr ferritic/martensitic ODS steels developed by a direct powder forging route

ABSTRACT A nominal composition of mechanically alloyed Fe-9Cr-2W-0.2Ti-0.12C-0.35Y2O3 steel powders was consolidated via a direct powder forging route. The powder-forged samples exhibited an equiaxed grain structure with the formation of Y-Ti-O (Y2Ti2O7 or YTiO3) complex oxides and the absence of prior particle boundaries. The powder-forged samples were further heat treated, i.e. cooled at three different rates, i.e. furnace cooling, air cooling, and water quenching, followed by tempering for the air-cooled and water-quenched samples. The tensile strength at room temperature for water-quenched and normalised samples was comparable, whereas the ductility for the normalised samples was higher, while at high temperature, a good combination of strength and ductility was achieved in the tempered air-cooled samples among all the heat-treated samples. The mechanical properties achieved in the present study were at par and superior in some cases to those reported in literature. The absence of prior particle boundaries network, almost full density and equiaxed grains indicated that the powder forging route can emerge as an alternative consolidation technique to HIP and hot extrusion for the consolidation of powder metallurgy oxide dispersion strengthened steels for nuclear applications.

Influence of oxygen content on fatigue crack growth behavior of FGH96 superalloys

The fatigue crack growth (FCG) mechanism of FGH96 superalloys influenced by oxygen (O) was investigated in terms of grain structure and phase composition. The results reveal that the thinner powder oxide film process facilitates easier dissolution, and thus the fewer undissolved oxides as well as the movement of high-angle grain boundaries promote the generation of a uniform distributed small grains (SGs) within both the prior particle boundaries (PPB) interface and powder interior in the alloy with O content of 140 ppm. In contrast, the large number of undissolved oxide particles provides more recrystallization sites and thus the SGs clusters aggregate at the PPB interface in the alloy with O content of 340 ppm during sintering. A homogeneous distribution of SGs induces the uniform deformation of the alloy and thus stimulates the transgranular fracture of the coarse grains in alloy with O content of 140 ppm, in favor of a higher fatigue life. On the contrary, in the alloy with O content of 340 ppm, the SGs clusters forming on PPB interface results to the strain concentration at PPB, leading to the PPB fractured morphology and a serious reduction of the fatigue life. This study reveals that the generation of SGs is responsible for the FCG behavior and failure mechanism of the alloys, and suggests that regulating the uniform distribution of SGs or reducing the number of SGs during sintering plays an important role in improving the fatigue properties of powder metallurgy superalloys.

Phase and microstructure formation during reactive spark plasma sintering of AlxCoCrFeNi (x=0.3 and 1) high entropy alloys

This paper is one of the first studies focusing on phase and microstructure formation mechanisms during reactive sintering of AlxCoCrFeNi (x = 0.3, 1) high entropy alloys (HEAs). The alloys have been prepared by mechanical activation followed by spark plasma sintering (SPS). Both powders are subjected to gluing to the milling vials and the phenomenon intensifies with Al content, resulting in a more important mechanical alloying delay for the equiatomic composition. The temperature influence on phase and microstructure formation was investigated by SPS from 550 to 1100 °C. Al0.3CoCrFeNi reactive sintering led to a face-centered cubic (FCC) solid solution with a grain size around hundreds of nanometers with nanometric intergranular B2 precipitates which content and size reduced with the temperature increase. Grain growth was observed at prior particle boundaries due to dynamic recrystallization, a phenomenon that can be controlled through modification of the milling and sintering steps, leading thus to tailored grain sizes. For the AlCoCrFeNi composition, temperature increase favors secondary FCC formation and leads to sigma phase precipitation. A dual homogeneous-heterogeneous microstructure is obtained due to the important gluing leading to insufficient milling. The dynamic recrystallization at prior particle boundaries promotes also body-centered cubic (BCC) to FCC phase transition. Therefore, the proposed reactive sintering route allows to obtain, for the equiatomic composition, alloys exhibiting very fine microstructures, with higher FCC fraction content than by conventional metallurgy processes.

Microstructure and mechanical properties of Co31.5Cr7Fe30Ni31.5 high-entropy alloy powder produced by plasma rotating electrode process and its applications in additive manufacturing

Microstructure and mechanical properties of feedstock powders critically determine the quality of additive manufacturing (AM). The present study employs a plasma rotating electrode process (PREP) to produce non-equiatomic Co31.5Cr7Fe30Ni31.5 high-entropy alloy (HEA) powders and examines variations of their microstructure and mechanical properties with powder particle size in the range of 20–106 μm. It finds that the powders possess smooth surfaces, good sphericity, and equiaxed polycrystal grains under PREP electrode rod arc speed of 32000 r/min and main arc current of 760 A. A stable FCC structure is maintained regardless of the powder particle size. Moreover, the nano-hardness of the powders generally decreases with the increase of powder particle size except for that of 50–75 μm, which is positively correlated with the change of the grain size. The finest grain size is present for powders with particle sizes of 50–75 μm, which possess the highest average nano-hardness and reduced elastic modulus. Bulk alloys fabricated by cold spray (CS) and laser cladding (LC) AM maintain the FCC structure. The CSAM bulk alloy shows early brittle fracture due to the presence of pores and prior particle boundaries resulting from insufficient plastic deformation of the powder particles. The LCAM bulk alloy presents good tensile properties with the ultimate tensile strength (UTS) and elongation to failure being 481.2 MPa and 35.9%, respectively, which can be attributed to the good cohesion and grain characteristics. The present study shall provide the field of AM with useful information in the applications of non-equiatomic PREP HEA powders.

Anisotropic creep property related to non-spherical shape of mechanically alloyed powder of oxide dispersion strengthened F82H

Nanometric oxide particles dispersed within the matrix play an important role in improving the creep property of Oxide Dispersion Strengthened (ODS) steels. Conventional studies have primarily focused on investigating the distribution of the particles to control the creep property of ODS steels. However, achieving complete control over the creep property still poses challenges, as there are potentially other microstructural features like different matrices, micrometric precipitates, and inclusions derived from powder metallurgical processes that can influence it.In our previous research, we examined one such microstructural feature known as prior particle boundary (PPB). PPB refers to the surface of mechanically alloyed (MA) powder before consolidation. We revealed that the ODS steel with fine PPBs produced from smaller MA powder, exhibited shorter creep rupture times, compared to that with coarse PPBs produced from larger MA powder. This result was attributed to the increased formation of creep cavities on the PPBs in the ODS steel produced from smaller MA powder. Therefore, the size of MA powder affected the formation of creep cavity and had an impact on the creep property.In this study, we shifted our focus to the shape of MA powder with non-spherical shapes containing flake-like shape. Such shapes have the potential to induce anisotropy in the formation of creep cavities and/or the creep crack initiation and growth along anisotropic prior particle boundaries (PPBs), ultimately leading to anisotropic creep behavior.We conducted small punch creep tests on specimens with two different orientations to study the possible anisotropy. The results revealed that the creep rupture times varied depending on the orientation of specimen, thus indicating anisotropic creep property. This anisotropic creep property was related to the non-spherical shape of MA powder. This research highlighted the significance of managing the shape of MA powder in controlling the creep property of ODS steels.

Identification of the Mechanism Resulting in Regions of Degraded Toughness in A508 Grade 4N Manufactured Using Powder Metallurgy–Hot Isostatic Pressing

Powder metallurgy–hot isostatic pressing (PM-HIP) is a form of advanced manufacturing that offers the ability to produce near-net shape components that are otherwise not achievable via conventional forging or wrought manufacturing. Accessing the design space of PM-HIP is dependent upon the ability to achieve uniform or known properties in finalized components, which has resulted in a number of programs aimed at identifying properties achievable via PM-HIP manufacturing. One result of these programs has been the consistent observation of a variation in toughness observed for the low-alloy steel ASTM A508 Grades 3 and 4N. While observed, the degree of variability and the mechanism resulting in the variability have not yet been fully defined. Thus, a systematic approach to evaluate the variation observed in impact toughness in PM-HIP ASTM A508 Grade 4N was proposed to elucidate the responsible metallurgical mechanism. Four unique billets manufactured from two heats of powder with different particle size distributions (PSDs) were fabricated and tested for impact toughness and tensile properties. The degradation in impact toughness was confirmed to be location-specific where the near-can region of all billets had reduced impact toughness relative to the interior of each billet. The mechanism driving the location-specific property development was identified to be mobile oxygen that follows the thermal gradient that develops during the HIP cycle and leads to a redistribution of mobile oxygen where oxygen is concentrated ~1” inboard of the original canister/billet interface. Redistributed oxygen then forms stable oxides along coincident prior particle and prior austenite grain boundaries, effectively reducing the impact toughness. With the mechanism now addressed, necessary actions can be taken to mitigate the effect of the oxygen redistribution, allowing for use in PM-HIP A508 Grade 4N in commercial industry.

Microstructure characteristics of high strength-ductility powder metallurgy superalloy hot oscillatory pressed at sub-solvus temperatures

The early high-strength powder metallurgy superalloys used in aero engine are always prepared by hot isostatic pressing (HIPing) at sub-solvus temperature, but the as-HIPed materials experience prior particle boundaries (PPBs), thus the mechanical ductility is reduced. In order to eliminate the PPBs and obtain high ductility, the samples are fabricated by hot oscillatory pressing (HOPing). Microstructures of the samples are characterized by electron back scattering diffraction (EBSD), scanning electron microscopy (SEM) and so on. The results show that compared with hot pressed (HPed) samples, the HOPed samples present higher density, smaller grain size, lower PPBs scale, and enhanced room temperature tensile properties. The room temperature tensile strength and elongation at break of HOPed sample are 1417 MPa and 32.5 %, respectively, which is obviously better than those of HPed sample (1289 MPa and 20.3 %) and those of HIP sample (1363 MPa and 28.5 %). High strength-ductility is attributed to the accelerated densification and the inhibited PPBs induced by the oscillatory pressure.

Markedly enhancing mechanical properties of powder metallurgy superalloy by hot oscillatory forging

A powder metallurgy superalloy prepared by hot pressing (HP) was forged under static and oscillatory pressures. The microstructure, mechanical properties and fracture behavior of the sample before and after forging were characterized in detail. The results showed that the forging processes could effectively break the prior particle boundaries (PPBs) and reduce the PPBs precipitates, thus significantly improved the mechanical properties of the material. In particular, the hot oscillatory forging (HOF) process increased the tensile elongation and stress rapture life of the hot forged sample by 1.3 and 3.5 times, respectively. The present study suggests that HOF could be a promising technique for preparing high-performance superalloys.

Effect of rolling reduction on microstructure, mechanical properties and fracture features of hot isostatically pressed 30CrMnSiNi2A low alloy ultrahigh strength steel

As a powder metallurgy (PM) defect, existence of prior particle boundaries (PPBs) often makes mechanical properties visibly deteriorated. Hot rolling has been found to be an effective method of destroying PPBs. In present study, five different rolling reductions are applied to explore the effects of rolling reduction on evolution of PPBs in PM 30CrMnSiNi2A steels. Microstructure, mechanical properties and fracture modes of five samples are systematically analyzed and compared. Increase of rolling reduction not only makes Al-rich PPBs refined but also makes continuous PPBs structure gradually transform to dispersed oxides and short chain fragments, which can be attributed to deformation of powder particles. Change on distribution of PPBs leads to the variation of fracture modes. A strength-ductility-toughness balance is achieved when the rolling reduction scales up to 60 %. Although increase of rolling reduction causes grain refinement, work hardening and improvement of PPBs, it promotes formation of edge cracks. Occurrence of edge cracks is strongly associated with PPBs inclusions and makes ductility and toughness deteriorated.

Effects of Oxygen Content on Microstructure and Creep Property of Powder Metallurgy Superalloy

The effects of oxygen content on the microstructure and creep properties of the FGH96 superalloy were investigated. When oxygen content increased from 135 ppm to 341 ppm, the prior particle boundary (PPB) rose from degree 2 to degree 3, the size of the γ′ phase on PPB enlarged from 1.07 μm to 1.27 μm, and the MC carbide size grew from 77.4 nm to 104.0 nm. Meanwhile, the steady creep rate accelerated from 4.34 × 10−3 h−1 to 1.87 × 10−2 h−1, and the creep rupture life shortened from 176 h to 94 h, the creep rupture mode transferred from intergranular and transgranular mixed fracture to along PPB fracture. During creep, the micro-twin formation and gliding will be restrained by ∑3 boundaries. FGH96 superalloy with higher oxygen content contains less ∑3 boundaries, and its micro-twins cross-slipped instead of single-direction slip in lower oxygen content superalloy. Consequently, samples with a higher oxygen content crept faster and ruptured earlier.

Effect of Astroloy powder characteristics on mechanical properties of Powder-HIP components

Astroloy, Ni-based superalloy, with a high-volume fraction of γ', is beneficial for high temperature applications but, at the same time, has limited forgeability. For this reason, powder metallurgy (PM) is the only viable processing route for this alloy. In particular, Near Net Shape powder-HIPping (NNSHIP) is attracting much interest since it offers a possible solution to the high cost of PM production by reducing the amount of post-process forging and machining steps. However, this method still has some issues to overcome, such as the presence of prior particle boundaries (PPBs) decorated with carbides and/or oxides, which drastically reduce the material's mechanical properties. Many studies have attempted to solve this issue by optimizing HIP cycles and heat treatments (HTs), although powder characteristics, more specifically interstitial content, affect PPB presence and mechanical properties of HIP + HTed material. Additionally, powder boron content can have a major effect on material microstructure and mechanical properties. In this work, four powders with different particle size distribution (PSD), oxygen, carbon and boron content were studied. In doing so, the four powder batches and their HIP + HTed samples were fully characterized in terms of chemical composition, grain size and γ' system, and these properties were linked to the mechanical properties of the samples in order to define optimized powder characteristics. The optimized powder demonstrated more than 23 vol % of tertiary γ' due to a high boron content (259 ppm), a carbon content below 160 ppm, and an oxygen content below 150 ppm. With these characteristics, HIP + HTed Astroloy component obtained an improvement, with respect to the aeronautical AMS 5852B standard, of 7 % in ultimate tensile strength (UTS), 3 % in yield strength (YS), 84 % in elongation, 29 % in impact toughness and 22 % in hardness at room temperature. Additionally, at high temperatures, 760 °C, values are around the standard demands with an increase of 2 % in YS and a decrease of 7 % in UTS and 28 % in elongation, being the last one the best result obtained among the tested powders; also impact toughness at 760 °C presents a value close to room temperature requirements with 30 J.

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.

Processing, Microstructure, and Properties of Bimetallic Steel-Ni Alloy Powder HIP

This work explores technical feasibility in hot isostatic pressing (HIP) manufacturing of an integral bimetallic component using steel and Ni alloy powder for supercritical carbon dioxide (sCO2) turbomachinery. Lab-scale bimetallic HIP specimens using HAYNES® 282® and SS316L or SS415 powder are investigated in powder configuration, heat treatment, microstructure, and tensile properties up to 400 °C. Interdiffusion profiles at dissimilar alloy interfaces caused by HIP cycle is predicted by DICTRA simulations and validated by electron probe microanalysis (EPMA). The interdiffusion distance of most elements is around 100 μm, while C and N have a higher interdiffusion distance. Dense distribution of Ti-rich carbonitrides and alumina particles are found to decorate prior particle boundaries near joining interface on the 282 side, affecting tensile strength across interface as well as tensile failure location. A higher amount of excessive carbonitride formation near interface is observed in SS316L/282 than in SS415/282, which is consistent with the predicted greater degree of interdiffusion effect in SS316L/282. Typical HAYNES® 282® heat treatment condition is applicable to 282/SS316L and 282/SS415 combinations, resulting in a higher strength than cast CF8M and CA6NM. A pilot-scale bimetallic SS415/282 pipe is then demonstrated to show the promise of scaleup.

Effect of Microstructure on Corrosion Behavior of Cold Sprayed Aluminum Alloy 5083

This paper investigates the effect of the microstructure on the corrosion behavior of cold sprayed (CS) AA5083 compared to its wrought counterpart. It has been shown that the microstructure of CS aluminum alloys, such as AA2024, AA6061, and AA7075, affects their corrosion behavior; however, investigations of the corrosion behavior of CS AA5083 with a direct comparison to wrought AA5083 have been limited. The microstructure and corrosion behavior of CS AA5083 were examined by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS), electron backscattered diffraction (EBSD), electrochemical and immersion tests, and ASTM G67. The CS process resulted in microstructural changes, such as the size and spatial distribution of intermetallic particles, grain size, and misorientation. The refined grain size and intermetallic particles along prior particle boundaries stimulated the initiation and propagation of localized corrosion. Electrochemical tests presented enhanced anodic kinetics with high pitting susceptibility, giving rise to extensive localized corrosion in CS AA5083. The ASTM G67 test demonstrated significantly higher mass loss for CS AA5083 compared to its wrought counterpart due to preferential attack within prior particle boundary regions in the CS microstructure. Possible mechanisms of intergranular corrosion (IGC) propagation at prior particle boundary regions have been discussed.

Effect of Hf and Ta on Ni-based superalloy powders

The effect of Hf and Ta modifying on the microstructure and composition of Ni-based superalloy powders was investigated. The element concentrations on the powder surface and subsurface were quantitatively characterized by the Auger electron spectroscopy, and cross sections of powders were observed by the electron probe microanalysis. The results show that Hf and Ta hardly change the morphology of powders, but significantly change the powder surface and subsurface composition. Hf and Ta enhance the volume fraction of MC carbides in powders, thereby reducing the concentrations of C, Ti, and Nb on the powder surface and subsurface, which effectively inhibits the formation of the prior particle boundary during HIP. It reduces crack sources and thus improves the mechanical properties of the alloy.

Effect of hot rolling on microstructure and mechanical properties of hot isostatically pressed 30CrMnSiNi2A ultrahigh strength steel

The prior particle boundaries (PPBs) are a typical powder metallurgy (PM) defect, which usually leads to the deterioration of mechanical properties in PM materials. In this study, two different hot rolling modes (unidirectional rolling and cross rolling) are designed to improve PPBs in hot isostatic pressed (HIPed) 30CrMnSiNi2A ultrahigh strength steel. The microstructure, mechanical properties and fracture features of the HIPed compact, the hot unidirectional rolled (HURed) and hot cross rolled (HCRed) sheets are systematically compared. The results manifests that hot rolling has a significant influence on size and distribution of PPBs. PPBs in HIPed compact are comprised of Al-rich oxides which is distributed along particle boundaries. After hot rolling, large PPBs inclusions are crushed and the size of PPBs are mostly concentrated in 0–0.20 μm. Unidirectional rolling makes continuous PPBs structure broken into short-chain fragments and dispersed oxides completely, while cross rolling makes most of continuous PPBs structure maintained and only a few oxides are dispersed. Excellent mechanical properties are obtained by hot rolling, reflecting on an ultimate tensile strength (UTS) of about 2.0 GPa, a total elongation (TE) of 17.9 %, a Charpy impact energy of 28.6J along rolling direction and a UTS of over 2.1 GPa, a TE of 16.1 %, a Charpy impact energy of 18.1J along transverse direction, respectively. High performances can be attributed to formation of martensite, grain refinement, improvement of PPBs and work hardening. Furthermore, hot-rolled samples manifests an obvious anisotropy in mechanical properties. The HCRed sample reveals a lower anisotropy compared to the HURed sample, mainly owing to differences of PPBs distribution and rolling textures.

Improving the formability and mechanical properties of TiAl alloy by direct forging of uncondensed powder

The limited plasticity and poor formability of TiAl alloys constitute primary constraints on their widespread applicability. In this regard, an innovative forming method is proposed, characterized by the direct forging of unconsolidated pre-alloyed Ti–48Al–2Cr–2Nb powders. In this procedure, spherical powders with a broad particle size distribution are pre-encapsulated and subjected to vacuumed treatment, followed by direct high-temperature forging to attain the final desired shape. Throughout the process, the powders undergo pre-heating to various forming temperatures and are forged at different speeds, enabling a comparative analysis of the effect of forging temperature and speed on densification and the microstructural characteristics of the forged billet. Experimental results indicate that the powders can be nearly fully densified when direct forging is conducted within the α-phase region. By combining the finite element modeling and microstructural characterization, three mechanisms dominating the consolidation process of powders are revealed. Initial particle clustering and spatial rearrangement predominantly occur during the early deformation stage, enhancing densification. Subsequent fragmentation of particles, induced by severe plastic deformation, governs the entire deformation process, leading to the elimination of the prior particle boundaries and substantial densification improvement. The closure of the micrometer-scale voids is controlled by high-temperature diffusion and creep, which plays a pivotal role in weakening the detrimental effect of micro defects on mechanical properties. The above mechanisms act alternately or simultaneously, resulting in a homogeneous microstructure composed of α2+γ lamellae and bulk γ with small sizes, and a good synergy of strength and ductility. Therefore, this novel approach holds considerable potential as a cost-effective alternative strategy for producing TiAl components.

Formation and elimination mechanisms of prior particle boundaries in a new powder metallurgy superalloy

The formation of prior particle boundaries (PPBs) in a new powder metallurgy superalloy during hot isostatic pressing (HIP) is investigated. Also, the impact of subsequent hot deformation on the elimination of PPBs is systematically studied. The PPBs involves large γ′ phases, carbides (MC and M6C) and oxides (Al2O3, SiO2 and ZrO2). The reactions among the superficial oxides, the adsorbed C and O elements on the particle surface and internally-migrated alloying elements are the dominant reasons for the formation of PPBs during HIP. Besides, the existence of surface tension and surface energy induces the carbon segregation, as well as the formation of PPBs. Thus, the density of PPBs decreases when the spacing between powders is shrunk by a rapid deformation. In hot forming process, the PPBs can be efficiently eliminated via raising deformation temperature/true strain or reducing strain rate. The interactions between dislocations and PPBs, as well as the occurrence of dynamic recrystallization (DRX) induced by the strain/orientation gradient, lead to the elimination of PPBs. The thermodynamic stability of carbides declines with the raised temperature. It indicates that the dissolution of carbides and the elimination of PPBs can be accelerated via raising the deformation temperature. The breakage or deformation behavior of PPBs during hot extrusion is investigated by numerical simulation. The deformation degree of PPBs increases with the raised extrusion ratio. The above important findings are useful for developing hot extrusion processing to effectively eliminate PPBs.

Relationship Between Powder Size, Prior Particle Boundaries and Properties of FGH4096M Nickel-Based Superalloy

Relationship Between Powder Size, Prior Particle Boundaries and Properties of FGH4096M Nickel-Based Superalloy

Mechanical properties and microstructural analysis of ultra-fine grained Ni-based ODS alloy processed by powder forging

In the present study powder forging was employed to consolidate mechanically alloyed Ni-20Cr-20Fe-0.6Y2O3 Ni-based ODS powder. A mild steel can was filled with the mechanically alloyed powder and heated to 1200 °C in a Ar+H2 (90:10) atmosphere and hot forged in a channel die. The forged slab was characterized in terms of residual porosity, microstructure, oxide particle size and mechanical properties at room as well as elevated temperatures. The forged slab exhibited close to full density (> 99%), ultra-fined grain size of ∼503 nm and an average oxide particle size of 25.6 nm. Enhanced mechanical properties at room and elevated temperatures were obtained due to a combination of ultra-fine grains and uniform distribution of oxide particles. The high strain rates involved during powder forging cause the breaking or shearing out the oxide layer, oxide particles, and other prior particle boundary (PPB’s) forming compounds present on the surface of the particles and dispersing them into the grains interior and along the grain boundaries. The exposed material and sliding due to shear stress also enhances strong metallurgical bonding across collapsed interfaces and consequently improves mechanical properties. The absence of prior particles boundaries (PPB) network, nearly isotropic properties and almost full density indicated that the powder forging route can emerge as an alternative consolidation technique to HIP and hot extrusion for the consolidation of powder metallurgy ODS superalloys.