Microstructure Evolution of Mg-10Gd-2Y-0.5Zn-0.3Zr Alloy during Isothermal Forging Process

2014 ◽  
Vol 783-786 ◽  
pp. 485-490
Author(s):  
De Bin Shan ◽  
X.Z. Han ◽  
Wen Chen Xu
Keyword(s):  
Microstructure Evolution ◽  
Ageing Time ◽  
High Strength ◽  
Aged Alloy ◽  
Secondary Phases ◽  
Obvious Effect ◽  
Isothermal Forging ◽  
Forging Process ◽  
The Matrix ◽  
Peak Aged

The isothermal forging process of a bracket and its microstructure evolution of Mg-10Gd-2Y-0.5Zn-0.3Zr alloy have been investigated in the present study. The results show that the bracket with thin-web and high-rib is well formed through modifying corners and adding an active damping block into male die. Amounts of lamellae and particles distribute uniformly on the matrix after the isothermal forging process and ageing process. The isothermal forging process has an obvious effect on the precipitation behaviour of secondary phases, while it did not change the grain size greatly. With the increase of ageing time, more secondary phases precipitate from α-Mg matrix until 60h. The optimal ultimate tensile strength and elongation of the peak-aged alloy are 382MPa and 4.03%, respectively. The combined effects of LPO and β′ phases contribute to the high strength of the peak-aged alloy.

Effects of Die Temperature on Microstructure Evolution of 7A85 Aluminum Forging

2014 ◽  
Vol 633-634 ◽  
pp. 628-633
Author(s):  
Jian Liang Hu ◽  
You Ping Yi ◽  
Shi Quan Huang
Keyword(s):  
Uniform Distribution ◽  
Microstructure Evolution ◽  
Isothermal Forging ◽  
Forging Process ◽  
Medium Scale ◽  
Aluminum Forging ◽  
Die Temperature ◽  
Precipitated Phases ◽  
High Degree ◽  
Distribution Of Dislocations

The free forging process of medium scale specimen was carried out to study the effects of the die temperature on the microstructure evolution of 7A85 aluminum forging. The results show that with the increase of die temperature, the size of the grains and the distribution of dislocations and precipitates of free forging tend to have a high degree of uniformity. Considering the effects of die temperature, the isothermal forging process was applied for the deformation of complex aviation forging. The metal flows smoothly during the isothermal forging process and thus there is little possibility of forming unfill, crack and other defects. The dislocations are evenly distributed during the isothermal forging process. Consequently, there is a relatively uniform distribution of precipitated phases of the aviation forging.

Effect of Heat Treatment Conditions on Microstructures and Mechanical Properties of Cu-9Ni-6Sn-0.22Nb Alloy

2021 ◽  
Vol 904 ◽  
pp. 124-130
Author(s):  
Si Yang Xu ◽  
Ying Long Li ◽  
Mu Xin Zhang ◽  
Yi Fu Jiang ◽  
Hua Ding
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Electrical Conductivity ◽  
Grain Boundaries ◽  
Spinodal Decomposition ◽  
Ageing Time ◽  
High Strength ◽  
Ageing Temperature ◽  
Treatment Conditions ◽  
The Matrix

Due to its high strength, excellent electrical conductivity and high resistance to stress corrosion, Cu-Ni-Sn alloy has been selected as a kind of advanced metal material which can be used as the manufacture of springs, connectors, bearings and so on. In addition, the addition of Nb can efficiently improve the comprehensive properties of the alloy. In the present work, the effect of heat treatment conditions on microstructure and mechanical properties were studied in a Cu-9Ni-6Sn-0.22Nb alloy by means of optical microscopy (OM), transmission electron microscopy (TEM), tensile test and microhardness tests. The results show that before ageing, a large number of fine γ precipitates with DO22 type structure are distributed on the matrix. With the prolongation of ageing time, the ultimate tensile strength (UTS), yield strength (YS) and Vickers hardness increased firstly, and then decline. The reason can be attributed to the occurrence of spinodal decomposition and the formation of discontinuous precipitation (DP). At first, spinodal decomposition induced the enhanced interaction between dislocations and internal stress field, resulting in an increase of mechanical properties. Then the increased DP at grain boundaries leads to the decline of strength in the material. Finally, the relationship between the microstructure and the electrical conductivity was also analyzed, and the results show that the electrical conductivity increased with ageing time/ageing temperature increasing for the present alloy. Through the analysis of Matthiessen’ s rule, the variation of electrical resistivity depends on precipitates, solute atoms, dislocations, vacancies and grain boundaries, and the precipitates play an important role among them. Besides, more precipitates improve electrical conductivity. Therefore, the increase of ageing time/ageing temperature induced the increase of DP, resulting in an increase of electrical conductivity.

Role of Recrystallized Grains on the Environment-Assisted Cracking of Aluminium-Alloy

2013 ◽  
Vol 753 ◽  
pp. 489-492
Author(s):  
M. Bobby Kannan
Keyword(s):  
Heat Treatment ◽  
Grain Boundary ◽  
Strain Rate ◽  
Aluminium Alloy ◽  
High Strength ◽  
Test Methods ◽  
Aged Alloy ◽  
Rate Testing ◽  
Peak Aged

In this study, the role of recystrallized grains on the environment-assisted cracking (EAC) susceptibility of a high strength aluminium alloy (Al-Zn-Mg-Cu) was examined using slow strain rate testing (SSRT) and U-bend test methods in chloride-containing solution. Experimental results suggest that the recrystallized grains in the peak-aged alloy are more prone to EAC. However, by altering the morphology and chemistry of the grain boundary precipitates of the recrystallized grains by overaging heat treatment, the alloy susceptibility to EAC reduced significantly.

scholarly journals Precipitate Evolution and Fatigue Crack Growth in Creep and Artificially Aged Aluminum Alloy

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1039
Author(s):  
Chi Liu ◽  
Yilun Liu ◽  
Liyong Ma ◽  
Songbai Li ◽  
Xianqiong Zhao ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Resistance ◽  
High Strength ◽  
Dislocation Slip ◽  
Aged Alloy ◽  
Precipitation Process ◽  
The Matrix ◽  
Creep Time ◽  
Strengthening Phases

The fatigue performance of high-strength Al-Cu-Mg alloys is generally influenced by the process of creep age formation when applied to acquire higher strength. The results show that creep aging accelerates the precipitation process, leading to a more uniform precipitation of strengthening phases in grains, as well as narrowed precipitation-free zones (PFZ). Compared with the artificially aged alloy, the yield strength and hardness of the creep aged alloy increased, but the fatigue resistance decreased. In the low stress intensity factor region (ΔK ≤ 7 MPa·m1/2), the fatigue crack propagation (FCP) rate was mainly affected by the characteristics of precipitates, and the fatigue resistance noticeably decreased with the increased creep time. In a 4 h creep aged alloy, the microstructure was dominated by Cu-Mg clusters and Guinier-Preston (GP) zones, while S″ phases began to precipitate in the matrix, showing better fatigue resistance. After aging for 24 h, the needle-shaped S’ phases were largely precipitated and coarsened, which changed the mode of dislocation slip, reduced the reversibility of slip, and accelerated the accumulation of fatigue damage. In stable and rapid crack propagation regions, the influence of precipitates on the FCP rate was negligible.

scholarly journals Microstructure Evolution of the Semi-Macro Segregation Induced Banded Structure in High Strength Oil Tubes During Quenching and Tempering Treatments

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3310 ◽  
Author(s):  
Bo Li ◽  
Ming Luo ◽  
Zhanbing Yang ◽  
Feifei Yang ◽  
Huasong Liu ◽  
...  
Keyword(s):  
Cooling Rate ◽  
Microstructure Evolution ◽  
High Strength ◽  
Oil Well ◽  
High Concentration ◽  
Corrosive Media ◽  
Obvious Effect ◽  
Tempering Temperature ◽  
Banded Structure ◽  
Quenching And Tempering

C110 oil well casing tubes should have high strength and corrosion resistance which is commonly used for deep wells operation containing corrosive media. In this paper, the microstructure evolution of a kind of semi-macro segregation originated banded structure in casing tubes is studied under different heat treatments. It is shown that the characteristics of the banded structure will change significantly in subsequent hot working and heat treatment processes. For the hot-rolled ones, the banded structure is composed of pearlite plus bainite. After quenching, it evolves into martensite band with high concentration solute elements. Finally, the banded structure will change into a carbide banding under the following tempering process. The temperature and cooling rate of the tempering practice show an obvious effect on the final band structure. To improve anti-SSC (sulfide stress corrosion cracking) performance, the favorable QT (quenching and tempering) practice for C110 steel should be a higher tempering temperature and a quicker cooling rate, from which the banded structure defects can be decreased together with an obvious improvement of the tube wall hardness uniformity.

Effect of ECAP Prior to Aging on Microstructure, Precipitation Behaviour and Mechanical Properties of an Al-Cu-Mg Alloy

2018 ◽  
Vol 385 ◽  
pp. 290-295 ◽  
Author(s):  
Ivan Zuiko ◽  
Marat Gazizov ◽  
Rustam Kaibyshev
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Microstructure Evolution ◽  
Thermomechanical Processing ◽  
High Strength ◽  
Mg Alloy ◽  
Angular Pressing ◽  
Precipitation Behaviour ◽  
Peak Aged

Microstructure, precipitation behaviour and mechanical properties of an Al-5.64Cu-0.33Mn-0.23Mg-0.14Zr-0.11Ti (in wt. %) alloy subjected to thermomechanical processing (TMP) involving equal-channel angular pressing (ECAP) at ambient temperature to total strains (ε) of ~1 and ~2 followed by aging at 180°C for 0-28 h have been investigated and compared with conventional aging at the same temperature (T6 state). TMP led to significant increase in yield stress (YS) and ultimate tensile strength (UTS) and decrease in elongation-to-fracture as compared to the peak-aged T6 state. The YS, UTS and δ values attained after ECAP to ε ~ 2 followed by peak ageing were ~510 MPa, ~540 MPa and ~7.6%, respectively. The changes in mechanical properties were related to microstructure evolution and precipitation behaviour. TMP conditions obtaining a high-strength state of the Al-Cu-Mg alloy are discussed.

scholarly journals Comparative Study of Two Aging Treatments on Microstructure and Mechanical Properties of an Ultra-Fine Grained Mg-10Y-6Gd-1.5Zn-0.5Zr Alloy

Metals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 658 ◽  
Author(s):  
Huan Liu ◽  
He Huang ◽  
Ce Wang ◽  
Jia Ju ◽  
Jiapeng Sun ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Magnesium Alloys ◽  
Aging Treatment ◽  
High Strength ◽  
Tensile Tests ◽  
Aged Alloy ◽  
Fine Grained ◽  
Peak Aging ◽  
Peak Aged ◽  
Strength And Ductility

Developing high strength and high ductility magnesium alloys is an important issue for weight-reduction applications. In this work, we explored the feasibility of manipulating nanosized precipitates on LPSO-contained (long period stacking ordered phase) ultra-fine grained (UFG) magnesium alloy to obtain simultaneously improved strength and ductility. The effect of two aging treatments on microstructures and mechanical properties of an UFG Mg-10Y-6Gd-1.5Zn-0.5Zr alloy was systematically investigated and compared by a series of microstructure characterization techniques and tensile test. The results showed that nano γ’’ precipitates were successfully introduced in T5 peak aged alloy with no obvious increase in grain size. While T6 peak aging treatment stimulated the growth of α-Mg grains to 4.3 μm (fine grained, FG), together with the precipitation of γ’’ precipitates. Tensile tests revealed that both aging treatments remarkably improved the strengths but impaired the ductility slightly. The T5 peak aged alloy exhibited the optimum mechanical properties with ultimate strength of 431 MPa and elongation of 13.5%. This work provided a novel strategy to simultaneously improve the strength and ductility of magnesium alloys by integrating the intense precipitation strengthening with ductile LPSO-contained UFG/FG microstructure.

Research on Microstructure Evolution Laws of Ultrafine Grained Metastable Automobile Steel

2013 ◽  
Vol 423-426 ◽  
pp. 281-285
Author(s):  
Ji Guang Li ◽  
Hai Liang Huang ◽  
Shang Wu Zeng ◽  
Jia Li Cao ◽  
Tie Jun Wang
Keyword(s):  
Microstructure Evolution ◽  
Retained Austenite ◽  
Large Fraction ◽  
Lath Martensite ◽  
High Strength ◽  
Ultrafine Grain ◽  
High Plasticity ◽  
Ultrafine Grained ◽  
The Matrix ◽  
Evolution Laws

The microstructure evolution laws of ultrafine grained metastable automobile steels was studied in this paper by laser confocal scanning microscope, EBSD, XRD and TEM. Results showed that, the matrix organizations of hot-rolled steel were lath martensite and deformation ferrite, and there were a little of retained austenite film and lath between the lath martensite. After heat treatment, the matrix organizations of steel were ultrafine ferrite and retained austenite. The retained austenite transformed into martensite and ε-martensitic in the deformation process, and the strength and plasticity of steel were improved. A lot of retained austenite were obtained in the annealing process. The TRIP effects by the large fraction of metastable austenite and the ultrafine grain size add to the test steel with high strength and high plasticity.

Deformation and fracture behavior of an Al-Li-Cu-Mg-Zr alloy 8090

1990 ◽  
Vol 48 (4) ◽  
pp. 974-975
Author(s):  
D.M. Jiang ◽  
B.D. Hong
Keyword(s):  
High Strength ◽  
Deformation And Fracture ◽  
Fracture Behaviors ◽  
Aluminum Lithium ◽  
Carbon Fiber Reinforced Composites ◽  
Peak Aged ◽  
Aluminum Lithium Alloys ◽  
High Strength Aluminum Alloys ◽  
Lithium Alloys ◽  
Zr Alloy

Aluminum-lithium alloys have been recently got strong interests especially in the aircraft industry. Compared to conventional high strength aluminum alloys of the 2000 or 7000 series it is anticipated that these alloys offer a 10% increase in the stiffness and a 10% decrease in density, thus making them rather competitive to new up-coming non-metallic materials like carbon fiber reinforced composites.The object of the present paper is to evaluate the inluence of various microstructural features on the monotonic and cyclic deformation and fracture behaviors of Al-Li based alloy. The material used was 8090 alloy. After solution treated and waster quenched, the alloy was underaged (190°Clh), peak-aged (190°C24h) and overaged (150°C4h+230°C16h). The alloy in different aging condition was tensile and fatigue tested, the resultant fractures were observed in SEM. The deformation behavior was studied in TEM.

CARPENTER CUSTOM 475

Alloy Digest ◽  
2006 ◽  
Vol 55 (9) ◽  
Keyword(s):  
Tensile Strength ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Small Diameter ◽  
High Strength ◽  
Heat Treating ◽  
Good Corrosion Resistance ◽  
Technology Corporation ◽  
Peak Aged ◽  
Carpenter Technology Corporation

Abstract Custom 475 stainless is a premium melted, high-strength, martensitic, precipitation-hardenable stainless steel. It provides good corrosion resistance and was designed to achieve a tensile strength up to 2000 MPa (290 ksi), combined with good toughness and ductility when in the H975 condition, peak aged at 525 deg C (975 deg F). Other combinations of strength are possible by applying aging temperatures up to 595 deg C (1100 deg F). The alloy is available in strip, wire, and small diameter bar. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, and machining. Filing Code: SS-974. Producer or source: Carpenter Technology Corporation.

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