Effect of cold deformation on age hardening of alloy VT35

2004 ◽  
Vol 46 (11-12) ◽  
pp. 535-538 ◽  
Author(s):  
V. A. Volodin ◽  
B. A. Kolachev ◽  
V. N. Moiseev ◽  
A. I. Vorob’ev ◽  
E. A. Ashivkina
Keyword(s):  
Cold Deformation ◽  
Age Hardening ◽  
Alloy Vt35

Effect of Cold Deformation on Microstructure and Mechanical Properties of Mg-8Gd-3Y-0.5Zr Alloy

2012 ◽  
Vol 706-709 ◽  
pp. 1297-1302
Author(s):  
De Jiang Li ◽  
Xiao Qin Zeng ◽  
Xin Su ◽  
Yan Cai Xie ◽  
Wen Jiang Ding
Keyword(s):  
Mechanical Properties ◽  
Cold Rolling ◽  
Cold Deformation ◽  
Tensile Tests ◽  
Age Hardening ◽  
Boundary Structure ◽  
Microstructure Observation ◽  
Microstructure And Mechanical Properties ◽  
Peak Aging ◽  
State 1

Pre-cold rolling with the reduction of 15% was employed on Mg-8Gd-3Y-0.5Zr (wt.%) (GW83K) alloy in different initial states: as-extruded (state 1) and extruded followed by annealing (state 2) with the aim to investigate the effects on microstructure and mechanical properties. Microstructure observation revealed that there are more amounts of mechanical twins in the alloy in state 2 than that of the alloy in state 1 after cold rolling, which indicates the different deformation mechanisms. Further investigation through EBSD has elucidated the grain boundary structure and types of twins in the alloys. Pre-cold deformation greatly promotes the age hardening response and the peak aging time at 200°C was found to be nearly 12h for the alloy in both state 1 and state 2, which were about 24h and 80h less than that of their non-deformed counterparts, respectively. Tensile tests at temperatures lower than 250°C showed that the alloy in state 1 has a predominant mechanical property than that of the alloy in state 2, while at 300°C, it displayed a reverse tendency.

TEM Study for Strengthening Mechanisms in Elgiloy

2010 ◽  
Vol 442 ◽  
pp. 268-274 ◽  
Author(s):  
I.N. Qureshi ◽  
S. Rani ◽  
F. Yasmin ◽  
M. Farooque
Keyword(s):  
Electron Microscope ◽  
Cold Work ◽  
Cold Deformation ◽  
Solution Treatment ◽  
Optical Microscope ◽  
Age Hardening ◽  
Solution Treated ◽  
Transmission Electron ◽  
P Transformation ◽  
Cold Worked

Elgiloy is Co based alloy (40wt%Co, 20wt%Cr, 15wt%Ni, 14wt%Fe and 7wt%Mo). It was strengthened by cold work and is capable of additional hardening by aging. The effects of solution treatment, cold working and age-hardening on the microstructure of elgiloy were investigated using optical microscope, scanning electron microscope (SEM) and transmission electron microscope (TEM). As rolled strips were solution treated at 1065°C/1hr. These solution treated strips were then reduced 50% by cold rolling. After cold-deformation both є-hcp phase and fcc deformation twins are also considered to coexist at room temperature. The cold worked strips were then age hardened at (450-600)°C. The age hardened strips showed formation of additional є-phase (via α f c c є h c p transformation).

Age-Hardening Characteristics of Cu-Ni-Si Alloy after Cold Deformation

2012 ◽  
Vol 217-219 ◽  
pp. 294-298 ◽  
Author(s):  
Xiang Peng Xiao ◽  
Bai Qing Xiong ◽  
Qiang Song Wang ◽  
Guo Liang Xie ◽  
Li Jun Peng
Keyword(s):  
Heat Treatment ◽  
Electrical Conductivity ◽  
Aging Time ◽  
Cold Deformation ◽  
Solution Treatment ◽  
The Other ◽  
Age Hardening ◽  
Precipitation Strengthening ◽  
Peak Hardness ◽  
Strengthening Mechanisms

The microstructural features and heat treatment response of Cu-2.1Ni-0.5Si-0.2Zr-0.05Cr (wt.%) alloy have been investigated. The alloy was aged at 400°C、450°C and 500°C after a cold deformation of 70% reduction. The variation in hardness and electrical conductivity of the alloy was measured as a function of aging time. The results indicated the highest peak hardness value of approximately 205HV for the alloy aged at 400°C for 4h after the solution treatment and cold deformation. The alloy has two main phases, one is Ni2Si phase, and the other is Cr2Zr phase. The strengthening mechanisms of the alloy include spinodal decomposition strengthening, ordering strengthening and precipitation strengthening.

scholarly journals Prior Solutionising Deformation Consequence on the Aging Characteristics of Steel Powder Reinforced Al 7075 Composites

2019 ◽  
Vol 8 (2S11) ◽  
pp. 2256-2261
Keyword(s):  
Aluminum Alloy ◽  
Strain Hardening ◽  
Cold Deformation ◽  
Solution Treatment ◽  
Steel Powder ◽  
Heat Treatments ◽  
Age Hardening ◽  
Peak Hardness ◽  
Alloy Matrix ◽  
Al 7075

Globally, in the application of structural materials, aluminum composites are emerging as pioneer materials due to balanced properties like ductility, strength, hardness and weight to volume ratio. It is obvious that addition of harder steel powder reinforcements to the softer aluminum alloy matrix will yield in larger benefits as energy efficient method, durability and recyclability for the composite. Infact, improvement in hardness levels at low temperatures in softer matrix aluminium alloys is the order of the day for wear related applications. Aluminum alloy composites especially Al 7075 matrix containing solid state soluble elements like copper, zinc and silicon with or without wetting agents like magnesium are heat treatable and got medium strength. The alloy matrix dispersed with solid reinforcements like carbides, oxides, flyash and steel powder contribute for the property improvement by tailoring the suitable heat treatment with flexibility in process parameters. Cold deformation assisted heat treatments, prior to or post solutionising challenge conventional heat treatments like age hardening or precipitation hardening. When the cold deformation is provided before solution treatment increases hardness by strain hardening with increased nucleation sites for phase transformation. When partial solutionising is given to the cold deformed composite retains the partial strain hardening effect on the specimen compared to complete solutionising. The retention of partial strain hardening followed by further aging develops complex interaction effect of strain hardening coupled with controlled precipitation of intermetallics on the composite for drastic uplift in hardness property. During conventional age hardening hardness and strength of the samples increase. Reduction in peak hardness value with increasing aging temperature is the renowned behaviour of age hardenable composites. The obtained peak hardness value is further increasing when cold deformation is supported with prior intentional deformation. Considering these features, it is proposed to perform prior solutionising deformation followed by subsequent aging on the stir cast Al 7075 –steel powder reinforced composite and analyse the microstructure and hardness distribution pattern by varying the steel powder quantity (0, 3 and 6 wt%), deformation density (10 and 20%) and aging temperatures (100 and 180oC)

Modelling the Combined Effect of Room Temperature Storage and Cold Deformation on the Age-Hardening Behaviour of Al-Mg-Si Alloys-Part 1

2014 ◽  
Vol 794-796 ◽  
pp. 670-675 ◽  
Author(s):  
Ole Runar Myhr ◽  
Carmen Schafer ◽  
Øystein Grong ◽  
Olaf Engler ◽  
Henk Jan Brinkman ◽  
...  
Keyword(s):  
Room Temperature ◽  
Cold Deformation ◽  
Theoretical Background ◽  
Age Hardening ◽  
Room Temperature Storage ◽  
Hardening Model ◽  
Industrial Processing ◽  
Automotive Body ◽  
Multi Stage ◽  
Temperature Storage

In the present paper, an extended age hardening model for Al-Mg-Si alloys is presented. In this new approach the combined precipitation, yield strength and work hardening model, known as NaMo Version 1, has been further developed to account for the effects of room temperature storage and cold deformation on the resulting age hardening behaviour. Incorporation of these two new stages in NaMo largely increases the versatility of the model by allowing simulations of complex multi-stage industrial processing involving thermomechanical treatment as well. Part 1 of this work deals with the theoretical background and experimental validation of the extended version of NaMo, while Part 2 focuses on the new applications of the model by showing some numerical examples related to production of automotive body panels.

Post Solutionising Rolling Sway on the Precipitation Behaviour of Eutectoid Steel Powder Reinforced Al7075 Ternary Alloy Composites

2020 ◽  
Vol 995 ◽  
pp. 9-14
Author(s):  
Rajesh Bhat ◽  
Sathyashankara Sharma ◽  
M.C. Gowrishankar ◽  
Manjunath Shettar ◽  
Pavan Hiremath ◽  
...  
Keyword(s):  
Ternary Alloy ◽  
Cold Deformation ◽  
Solution Treatment ◽  
Steel Powder ◽  
Age Hardening ◽  
Peak Hardness ◽  
Second Phase ◽  
Eutectoid Steel ◽  
Alloy Matrix ◽  
Mechanical Working

The solitary distinguished thermal treatment to aluminium alloy matrix of nonferrous group with uniformly dispersed reinforcement particles is precipitation or age hardening with or without mechanical working. Al7075 ternary alloy composites belongs to Al-Zn-Mg group and bulk properties can be enhanced by the formation of the immensely small consistently spread out precipitates of solute rich second phase within the matrix phase. The treatment comprises solutionising (550°C) supported by controlled aging (100 and 180°C) below the solvus temperature of the given alloy. Aging expedites the diffusion of solute atoms to form secondary particles (intermetallics) from the room temperature super saturated solid solution. This process is supported by deformation known as rolling as post activity, develops strain hardening in matrix and reinforcement. The present work shows the distinction in the aging phenomenon on alloy and alloy matrix composites (reinforced with 3 and 6 wt% of eutectoid steel powder, 10-30 micron size) upon undergoing cold rolling prior to aging i.e., after solution treatment. The variation in the hardness distribution with aging kinetics for both aging temperatures with and without cold deformation (10 and 20%) in between the consecutive stages like, solution treatment and aging were investigated and peak hardness values were noted in each aging temperatures and results were analysed. In every hardness test 10 trials were performed and the average of 6 consistent readings are taken as the outcome. 20 to 40% improvement in peak hardness is observed with intentional deformation over without deformation. The composite may be used for light duty cold working dies where bulk hardness and frictional characteristics are very important.

Modelling the Combined Effect of Room Temperature Storage and Cold Deformation on the Age-Hardening Behaviour of Al-Mg-Si Alloys-Part 2

2014 ◽  
Vol 794-796 ◽  
pp. 722-727 ◽  
Author(s):  
Carmen Schäfer ◽  
Ole Runar Myhr ◽  
Henk Jan Brinkman ◽  
Olaf Engler ◽  
Jürgen Hirsch
Keyword(s):  
Room Temperature ◽  
Cold Deformation ◽  
Tensile Tests ◽  
Theoretical Background ◽  
Age Hardening ◽  
Extended Model ◽  
Artificial Ageing ◽  
Natural Ageing ◽  
Forming Process ◽  
Automotive Sheet

The present investigation deals with modelling of the age-hardening behaviour of 6xxx series automotive sheet alloys. The basis for this work is the established precipitation model NaMo developed for coupled nucleation, growth, dissolution and coarsening in Al-Mg-Si extrusion alloys. It has recently been extended for applicability for Al-Mg-Si automotive sheet alloys by incorporating the important effects of room temperature (RT) storage and deformation prior to the final artificial ageing of Al-Mg-Si sheet alloys. The 6xxx automotive sheet alloys change due to natural ageing during the time elapsing between their processing and their paint baking in the customers process. This RT storage time has an impact on the artificial ageing response during the OEMs paint baking cycle. A second effect originates from the deformation introduced in the material during the part forming process prior to the artificial ageing in the paint bake cycle. This deformation leads to the introduction of dislocations which further modify the artificial ageing response by providing heterogeneous nucleation sites for nucleation of additional strengthening phases. Part 1 of this work deals with the theoretical background and experimental validation of the extended version of NaMo, while Part 2 focuses on the new applications of the extended model by simulation of ageing during paint baking according to typical customer requirements. The model validation is based on a comprehensive set of tensile tests. A comparison between model predictions and measurements shows reasonable agreement, and it is concluded that, after some further development, the model can be used to model the yield strength response of 6xxx automotive sheet alloys incorporating the (combined) effects of natural ageing, deformation and the accurate heat treatments in the paint bake cycle.

Effect of Cold Deformation on the Paint-Baking Response of Al-Mg-Si Alloy Sheet for Automotive Body

2012 ◽  
Vol 706-709 ◽  
pp. 414-419
Author(s):  
Ni Tian ◽  
Lei Pan ◽  
Chun Cheng Liu ◽  
Jian Jun Wang ◽  
Gang Zhao ◽  
...  
Keyword(s):  
Yield Strength ◽  
Tensile Deformation ◽  
Cold Deformation ◽  
Alloy Sheet ◽  
Age Hardening ◽  
Scanning Calorimetry ◽  
Alloy Matrix ◽  
Automotive Body ◽  
Β Phase ◽  
Strength Increment

The effect of cold deformation on the yield strength and precipitate behavior of Al-1.3Mg-1.2Si-0.5Cu-0.7Mn alloy sheet subjected to T4P temper for automotive body panels before and after paint-bake treatment were investigated by tensile test and differential scanning calorimetry (DSC) analysis. The results show that the T4P alloy sheet has significant work-hardening response (WHR), and the yield strength increment exceeds 190MPa as the tensile deformation strain approaches 15%. The unstrained T4P alloy sheet has obvious paint-baking response (PBR), and the yield strength increment is up to 80MPa, while the PBR of the cold stretched T4P alloy sheets decrease with increasing level of tensile deformation, and the minimal PBR is only 17.8MPa. The prior tensile deformation accelerates the precipitation of β″ and β′ phase from the T4P alloy matrix during paint-bake cycle but weakens the age-hardening response (AHR) and PBR of T4P alloy sheet. Moreover, it is evident that the T4P alloy sheet simulation paint-bake treated at 170°C for 30min can not fully exert the aging potential of the alloy sheet.

Flow Stress Constitutive Equation of Age Hardening Cu-1.1Cr Alloy during Hot Compression Deformation

2011 ◽  
Vol 213 ◽  
pp. 623-627 ◽  
Author(s):  
Li Zhang ◽  
Ke Xing Song ◽  
Yan Min Zhang ◽  
Qing Wang ◽  
Wei Feng Liu
Keyword(s):  
Flow Stress ◽  
Constitutive Equation ◽  
Strain Rate ◽  
Cold Deformation ◽  
Solution Treatment ◽  
Hot Compression ◽  
Age Hardening ◽  
Hollomon Parameter ◽  
Hot Compression Deformation ◽  
Compression Deformation

The Cu-1.1Cr alloys performed in this paper were prepared by thermal deformation + solution treatment + cold deformation + aging treatment + machining. The flow stress behavior of Cu-1.1Cr alloy was investigated by isothermal compression on Gleeble-1500 hot simulator in the temperature range of 400-800°C and strain rate of 0.01-1s-1. The experimental results indicated that the flow stress of Cu-1.1Cr alloy depends on the strain rate and the deformation temperature. The flow stress increased with increasing strain rates and decreased with increasing temperature. The flow stress of Cu-1.1Cr alloy during hot compression deformation could be represented by Zener-Hollomon parameter including the Arrhenius term. The values of n, α and A in the analytical expressions of flow stress are fitted to be n=15.696, α=0.005178MPa-1 and A =1.289×1021s -1, respectively. The hot deformation activation energy is 346.738kJ/mol. The constitutive equation of the Cu-1.1Cr alloy was obtained .

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