Effect of Deposition Temperature on the Evolution of Texture,Grain Boundary Constitution and Corrosion Behaviour of Sn–Cr Coatings

Metallurgical and Materials Transactions A - Effect of deposition temperature on the evolution of microstructure and corrosion properties of electrodeposited SnCr coatings was studied. The coatings...     

Effect of Processing Condition on Texture and Drawability of a Ferritic Rolled and Annealed Interstitial-Free Steel

The processing conditions of the texture formation and deep drawability of a Ti-IF steel strip hot-rolled in ferritic region and subsequently annealed were investigated. The r-value increases with the decrease of reheating temperature, and finish rolling temperature and the increase of reductions in ferritic region. For lubricated ferritic rolling and annealing, the r-value is raised up to 1.75, and elongation rate is over 50% at the finish rolling temperature of 650 ℃, which is suitable for DDQ grade products. However, the r-value is below 1.0 in the case of unlubricated rolling. The X-ray diffraction was used to analyze the textural characteristic of samples. For samples subjected to lubricated rolling and annealing, the strong { 111 }//ND recrystallization texture is distributed homogeneously along the thickness direction, and the intensity of { 110} recrystallization texture is very low even in surface. However, for unlubricated samples, the {111} texture is distributed inhomogeneously and is weak along the thickness direction, and （110}//ND recrystallization texture is strong, which deteriorates the formability.     

Effect of Grain Size on Mechanical Properties of NickelFree High Nitrogen Austenitic Stainless Steel

The fine grained structures of nickelfree high nitrogen austenitic stainless steels had been obtained by means of cold rolling and subsequent annealing. The relationship between microstructure and mechanical properties and gain size of nickelfree high nitrogen austenitic stainless steels was examined. High strength and good ductility of the steel were found. In the grain size range, the HallPetch dependency for yield stress, tensile strength, and hardness was valid for grain size ranges for the nickelfree high nitrogen austenitic stainless steel. In the present study, the ductility of cold rolled nickelfree high nitrogen austenitic stainless steel decreased with annealing time when the grain size was refined. The fracture surfaces of the tensile specimens in the grain size range were covered with dimples as usually seen in a ductile fracture mode.     

Evolution of Texture,Strain, and Grain Boundary Constitution in Copper–Chromium Coatings and its Effect on Coating Corrosion Behavior

Metallurgical and Materials Transactions A - Microstructural alterations in electrodeposited Cu–Cr coatings (1.5, 3.6, and 6.5 wt pct Cr) and their impact on the coating corrosion behavior...     

Effect of Processing Condition on Texture and Drawability of a Ferritic Rolled and Annealed InterstitialFree Steel

The processing conditions of the texture formation and deep drawability of a TiIF steel strip hotrolled in ferritic region and subsequently annealed were investigated. The rvalue increases with the decrease of reheating temperature, and finish rolling temperature and the increase of reductions in ferritic region. For lubricated ferritic rolling and annealing, the rvalue is raised up to 175, and elongation rate is over 50% at the finish rolling temperature of 650 ℃, which is suitable for DDQ grade products. However, the rvalue is below 10 in the case of unlubricated rolling. The Xray diffraction was used to analyze the textural characteristic of samples. For samples subjected to lubricated rolling and annealing, the strong {111}∥ND recrystallization texture is distributed homogeneously along the thickness direction, and the intensity of {110} recrystallization texture is very low even in surface. However, for unlubricated samples, the {111} texture is distributed inhomogeneously and is weak along the thickness direction, and {110}∥ND recrystallization texture is strong, which deteriorates the formability.     

Impact of Volume Fraction and Size of Reinforcement Particles on the Grain Size in Metal–Matrix Micro and Nanocomposites

In metal–matrix micro and nanocomposites (MMCs and MMNCs), the presence and interactions of various strengthening mechanisms are not well understood, but grain boundary strengthening is considered as one of the primary means of improving the yield strength of composites. Owing to the importance of grain size on mechanical properties, it is necessary to be able to describe how incorporation of nanoparticles (NPs) in both powder metallurgy (PM) and solidification processing (SP) affects this critical property. In the present work, we provide a basis for an empirical equation that relates particle fraction and particle size to MMNC grain size for both PM and SP synthesis methods. The model suggests that NPs retard grain coarsening in PM MMNCs and also seems to describe the effect of reinforcement concentration on grain size in SP MMCs and MMNCs.     

Amorphous Intergranular Film Effect on the Texture and Structural Evolution During Cold-Rolling of Nanocrystalline Ni–Zr Alloys

Metallurgical and Materials Transactions A - The presence of amorphous intergranular films (AIFs) in nanocrystalline (NC) metals improves the mechanical properties and thermal stability. However,...     

Effect of Heat Input and Niobium on the Microstructure and Toughness of Coarse Grain Heat-Affected Zone in HSLA Steels

 The influence of Nb on the coarse grain heat-affected zone (CGHAZ) microstructure, mechanical property and the transformation kinetics of HSLA steels under different heat inputs, has been investigated. When welded at higher heat inputs (100~60kJ cm-1), impact toughness values of the steel without Nb are much higher than the steel with Nb, and the lowest span is 153J at 60kJ cm-1. But only a little higher values are observed at lower heat inputs (40~30kJ cm-1), and the highest span is 68J at 30kJ cm-1. Dilatation studies indicate continuous cooling transformation start temperatures (Ts) of CGHAZ for the steel with Nb are approximately 15~30°C lower than the steel without Nb at all heat inputs. Under higher heat inputs Nb in solid solution suppress ferrite transformation and promote the formation of granular bainite which has detrimental effect on impact toughness. Under lower heat inputs higher Charpy impact energy values in the steel with Nb are associated with the formation of low carbon self-tempered martensite.     

Formation and Control of Sharp {100}〈021〉 Texture in Electrical Steel

Electrical steel sheets with the orientation of{100}parallel to the surfaces have the most easymagnitization axes on surface,and thus can serve asthe ideal cores of electrical motors.The special fea-ture of this kind of electrical steel draws much atten-tion.Wiener[1]experi mentally obtained{100}tex-ture in electrical steel by controlling the secondaryrecrystallization through surface energy.Based onthe principle that{100}surface energyis the lowestinα-iron under lowvacuumor slight oxidation …     

Influence of the Initial Microstructure on the Reverse Transformation Kinetics and Microstructural Evolution in Transformation-Induced Plasticity–Assisted Steel

The reverse transformation behavior upon heating to intercritical temperature was studied in Fe-0.21C-2.2Mn-1.5Si (wt pct) alloy with three initial microstructures. One is the cold-rolled (CR) structure and two others are martensite having different fractions of retained austenite. The CR structure exhibits slower reverse transformation kinetics than martensite due to the lesser population of potent nucleation sites and coarse cementite particles. The film type of retained austenite at the martensite lath boundary contributes to the earlier start of the reverse transformation, because it can proceed as the growth of pre-existing retained austenite, which makes the nucleation process less critical. Besides, the growth of interlath austenite plays an essential role in the evolution of fine lath-type reverse-transformed microstructure, which was difficult to obtain from similar initial microstructures of martensite having negligible fraction of interlath austenite.     

Effect of Starting As-cast Structure on the Microstructure–Texture Evolution During Subsequent Processing and Finally Ridging Behavior of Ferritic Stainless Steel

Metallurgical and Materials Transactions A - Effect of the initial as-cast structure on the microstructure–texture evolution during thermomechanical processing of 409L grade ferritic...     

Dependence of the Grain Size in the Microstructure of Copper on the Rate of Deformation by “Helical Rolling–Pressing”

Metallurgist - The authors consider the refinement of the microstructure of copper (grade M1) on the rate of deformation using a “helical rolling-pressing” method. The deformation was...     

Observation of 〈001〉 dislocations and a mechanism for transgranular fracture on {001} in FeAl

Transmission electron microscopy of iron-rich, B2-structure, FeAl alloys which had been compressed at room temperature revealed the presence of 〈001〉 dislocations, in addition to APB-coupled 〈111〉 dislocations which are normally observed at room temperature. It appears that the 〈001〉 dislocations form through the interaction of the 〈111〉 dislocations. This reaction to produce 〈001〉 dislocations is outlined and shown to be energetically favorable. The production of these 〈001〉 dislocations on {100} planes is suggested to be a cause of transgranular cleavage on {100} in B2 alloys deforming by 〈100〉 slip.     

Effect of Ti（C,N）Precipitation on Texture Evolution and Fish-Scale Resistance of Ultra-Low Carbon Ti-Bearing Enamel Steel

 The Ti(C,N) precipitation and texture evolution in ultra-low carbon Ti-bearing enamel steel were studied to discover their correlation. Two different cooling paths of simulative coiling were adopted to gain different morphologies of Ti(C,N) precipitate in hot strips. It is found that the Ti(C,N) precipitate in hot strip using Path 2 (put into asbestos box and air cooled) are finer and much more in quantity than that in hot strip using Path 1 (held at 730 ℃ for 30 min and furnace cooled). The morphology of Ti(C,N) precipitate in hot strip has great effect on recrystallization texture in the subsequent cold-rolled annealed sheet. γ-fiber texture of strong recrystallization is gained in cold-rolled and annealed sheet came from Path 1. On the contrary, in the one came from Path 2, the γ-fiber texture is weak. This may be due to the pinning force of numerous fine Ti(C,N) precipitate which retard the growth of preferential nucleated {111} orientated grains. Annealed steel sheets in the test came from both paths have excellent fish-scale resistance.     

Effect of Ti Addition and Microstructural Evolution on Toughening and Strengthening Behavior of as Cast or Annealed Nb–Si–Mo Based Hypoeutectic and Hypereutectic Alloys

Room temperature fracture toughness along with compressive deformation behavior at both room and high temperatures (900 °C, 1000 °C and 1100 °C) has been evaluated for ternary or quaternary hypoeutectic (Nb–12Si–5Mo and Nb–12Si–5Mo–20Ti) and hypereutectic (Nb–19Si–5Mo and Nb–19Si–5Mo–20Ti) Nb-silicide based intermetallic alloys to examine the effects of composition, microstructure, and annealing (100 hours at 1500 °C). On Ti-addition and annealing, the fracture toughness has increased by up to ~ 75 and ~ 63 pct, respectively with ~ 14 MPa√m being recorded for the annealed Nb–12Si–5Mo–20Ti alloy. Toughening is ascribed to formation of non-lamellar eutectic with coarse Nb_ss, which contributes to crack path tortuosity by bridging, arrest, branching and deflection of cracks. The room temperature compressive strengths are found as ~ 2200 to 2400 MPa for as-cast alloys, and ~ 1700 to 2000 MPa after annealing with the strength reduction being higher for the hypoeutectic compositions due to larger Nb_ss content. Further, the compressive ductility has varied from 5.7 to 6.5 pct. The fracture surfaces obtained from room temperature compression tests have revealed evidence of brittle failure with cleavage facets and river patterns in Nb_ss along with its decohesion at non-lamellar eutectic. The compressive yield stress decreases with increase in test temperature, with the hypoeutectic alloys exhibiting higher strength retention indicating the predominant role of solid solution strengthening of Nb_ss. The flow curves obtained from high temperature compression tests show initial work hardening, followed by a steady state regime indicating dynamic recovery involving the formation of low angle grain boundaries in the Nb_ss, as confirmed by electron backscattered diffraction of the annealed Nb–12Si–5Mo alloy compression tested at 1100 °C.