Heat Treatment Variability Effects on the Mechanical Properties of Beta Solution Treated Ti-6Al-4V

2010 ◽  
Vol 638-642 ◽  
pp. 401-406
Author(s):  
J.R. Calcaterra

Beta solution heat treatment is used to increase the fatigue crack growth resistance of Ti-6AL-4V. Unfortunately, the beta solution heat treatment is very sensitive to maximum temperature, time at temperature and cooling rate. In order to determine the effect of these parameters on mechanical properties, several different titanium billets and forgings were heat treated at various times and temperatures. The forgings had differing amounts of work, reflecting the potential for thermomechanical processing differences seen in a die forged component. Fracture toughness and tensile tests were conducted on the billets and forgings. In addition, sections of each work piece were excised and examined microscopically. The results from the study indicate there is a significant effect of heat treatment on thicker section components. In these cases, grains near the surface may grow large, while being barely transformed near the center. The change in microstructure has an effect on mechanical properties. Material with the larger grains tends to have worse ductility, while the fracture toughness properties of the material tend to decrease with grain size.

2016 ◽  
Vol 51 (14) ◽  
pp. 1971-1977 ◽  
Author(s):  
NH Noor Mohamed ◽  
Hitoshi Takagi ◽  
Antonio N Nakagaito

The mechanical properties of cellulose nanofiber-reinforced polyvinyl alcohol composite were studied. Neat polyvinyl alcohol films, cellulose nanofiber sheets, and their nanocomposites containing cellulose nanofiber weight ratios of 5, 15, 30, 40, 45, 50 and 80 wt% were fabricated. Heat treatment by hot pressing at 180℃ was conducted on the specimens to study its effect to the mechanical properties and the results were compared with the non heat-treated specimens. Morphology of the composites was studied by scanning electron microscopy and the mechanical properties were evaluated by means of tensile tests. The results showed that increase of cellulose nanofiber content from 5 wt% to 80 wt% has increased the tensile strength of the composites up to 180 MPa, with cellulose nanofiber content higher than 40 wt% yielding higher tensile strength. The heat-treated specimens exhibited higher tensile strength compared to those of untreated specimens.


Author(s):  
S Wiesenmayer ◽  
M Merklein

Shear-clinching has proven to be a suitable technology for joining of high-strength materials. However, the mechanical properties of the upper joining partner are limited due to the high strains, which occur during the process. Therefore, shear-clinching of the high-strength aluminum alloy AA7075 in the T6 temper is not possible. Yet, the mechanical properties of hardenable alloys of the 7000 series can be influenced by a heat treatment. Thus, within the scope of this work, the joinability of the high-strength alloy AA7075 in shear-clinching processes in dependance of its temper is investigated. The as fabricated state F, the artificially aged T6 temper, a paint baked state and the naturally aged T4 temper are compared to the fully solution annealed W temper as well as to a retrogression heat-treated state. For retrogression heat treatment, a laser is used as heat source, heating up the alloy for a short term in order to only partially dissolve precipitations. The resulting mechanical properties are determined with uniaxial tensile tests. Moreover, the influence of the mechanical properties of AA7075 on the shear-clinching process, the joint formation and the resulting joint strength is analyzed.


2016 ◽  
Vol 877 ◽  
pp. 400-406 ◽  
Author(s):  
Hannes Fröck ◽  
Matthias Graser ◽  
Benjamin Milkereit ◽  
Michael Reich ◽  
Michael Lechner ◽  
...  

Precipitation hardening aluminium alloys are widely used for automotive applications. To enhance the application of aluminium profiles, improved formability is needed. Tailor Heat Treated Profiles (THTP) with locally different material properties attempt to increase formability e.g. in bending processes. Tailoring of local properties is obtained by a local short-term heat treatment, dissolving the initial precipitate state (retrogression) and still allowing subsequent ageing. In the present study, the dissolution and precipitation behaviour of the aluminium alloy EN AW-6060 T4 was investigated during heating with differential scanning calorimetry (DSC). Heating curves from 20 to 600 °C with heating rates of 0.01 up to 5 K/s were recorded. Interrupted heat treatments with different maximum temperatures were performed in a deformation dilatometer. Immediately afterwards, tensile tests were carried out at room temperature. The course of the recorded mechanical properties as a function of the maximum temperature is discussed with regard to the dissolution and precipitation behaviour during heating. Finally, the aging behaviour of the investigated alloy was recorded after different typical short-term heat treatments and is discussed with reference to the DSC‐curves. The correlation of the microstructure and the mechanical properties enables the derivation of optimal parameters for the development of THTP through a local softening.


2011 ◽  
Vol 284-286 ◽  
pp. 1621-1625 ◽  
Author(s):  
Bai Ping Mao ◽  
Jun Peng Li ◽  
Jian Shen

Effects of thermo-mechanical treatment on the mechanical properties and microstructure of 2197 alloy were studied through analyses of the mechanical properties by tensile tests and TEM observation of thermo-mechanical heat treated 2197 alloy plates of various states. Results show that the dominating precipitated phase of peak-aged 2197 alloy during thermo-mechanical heat treatment is T1 phase of which the size is 50~150nm. The precipitation and growth of T1 phase are accelerated due to the existed nucleation sites for heterogeneous nucleation of T1 phase offered by thermo-mechanical treatment, therefore, the time for 2197 alloy to reach the peak-aged state is shorten. The strength of 2197 alloy for peak-aged state is increased through thermo-mechanical treatment because the strengthening effect of T1 phase with higher aspect ratio is bigger than that of δ′ and θ′ phases.


Author(s):  
Osita Obiukwu ◽  
Henry Udeani ◽  
Progress Ubani

The effect of various heat treatment operations (annealing, normalizing, tempering) on mechanical properties of 0.35% carbon steel was investigated. The change in the value of endurance limit of the material as a result of the various heat-treatment operations were studied thoroughly. It was found that the specimens tempered at low temperature (200°C) exhibited the best fatigue strength. Microscope was used to characterize the structural properties resulting from different heat treatment processes. The results from the tensile tests impact tests and hardness tests showed that the mechanical properties variate at every heat-treatment conditions. The microstructure of differently heat-treated steels was also studied.


2012 ◽  
Vol 504-506 ◽  
pp. 375-380 ◽  
Author(s):  
Marion Merklein ◽  
Michael Lechner ◽  
Thomas Schneider ◽  
Raoul Plettke

Aluminum profiles are well-established components in lightweight constructions. However, these profiles have a small forming capability in comparison to steel profiles, which leads to a limitation in their application. Within this paper a new and innovative approach for the enhancement of the forming limit of aluminum profiles under bending load called Tailored Heat Treated Profiles (THTP) is presented. With THTP the mechanical properties of the material are locally modified by a short-term heat treatment. By this local modification the material flow during the following cold bending operation can be influenced. For the design of the heat treatment layout, the correlation between the heat treatment parameters and the material properties has to be investigated. Tensile specimens were cut out of the profile and were subsequently completely heat treated with a laser. The changes of the mechanical properties caused by the heat treatment were analyzed by tensile tests. However, with a complete softening of the profile, the formability could not be improved. To increase the formability a local heat treatment, which leads to partial softening of the profile, has to be investigated. In order to characterize the heat-affected zone (HAZ) of the laser treatment, thermal camera and microhardness measurements were carried out. Appropriate heat treatment layouts have to be found to enhance the forming limit. Different layout strategies were developed and afterwards validated by the heat treatment and forming of profiles. This paper will present the findings of this investigation and show that THTP can be used to improve the formability of aluminum profiles for bending operations.


2012 ◽  
Vol 190-191 ◽  
pp. 1306-1310 ◽  
Author(s):  
Ming Bo Yang ◽  
Hong Liang Li ◽  
Ren Ju Cheng ◽  
Hong Jun Hu

In this paper, the effects of Sb addition on heat-treated microstructure and mechanical properties of AZ61-0.7Si magnesium alloy were investigated. The results indicate that the solution heat treatment can modify the Chinese script shaped Mg2Si phase in the AZ61-0.7Si alloy. After solutionized at 420°C, the morphology of the Mg2Si phase in the AZ61-0.7Si alloy changes from the Chinese script shape to the short pole and block shapes, and the higher modification efficiency could be obtained for the alloy with the addition of 0.4 wt.%Sb. In addition, the effect of the solution heat treatment on the morphology of the Mg2Si phase can also result in the improvement of tensile and creep properties for the AZ61-0.7Si alloy. After solutionized at 420°C for 24h and followed by aging treatment at 200°C for 12h, the AZ61-0.7Si alloy exhibits higher tensile and creep properties than that of the as-cast alloy, and the properties improvement resulted from heat treatment, is more obvious for the AZ61-0.7Si alloy with the addition of 0.4 wt.%Sb.


2019 ◽  
Vol 57 (3A) ◽  
pp. 11 ◽  
Author(s):  
Khanh Cong Huynh

Type 6201 aluminium alloy wires are produced by drawing 4.7 mm diameter billet-on-billet extruded redraw rod down to 2.7 mm diameter wires. Before drawing, the first group of redraw rod coils was annealed at 480oC for 4 hours to reduce the hardness of the redraw rod. The second group of redraw rod coils was drawn without annealing. With each group of redraw rod, after drawing, some wire coils were solution heat treated, then artificially aged or naturally aged. The other wire coils were artificially aged or naturally aged without solution heat treatment. Mechanical properties of the wires were assessed by a tensile testing machine (model UTM-1000)With suitable aging temperature and aging time, wires produced from each group of redraw rod coils with or without solution heat treatment attain tensile requirements of ASTM B398, but wires produced with solution heat treatment attain higher elongation than wires produced without solution heat treatment.


2006 ◽  
Vol 116-117 ◽  
pp. 181-184 ◽  
Author(s):  
Antonio Forn ◽  
Maite T. Baile ◽  
Enric Martín ◽  
Javier Goñi ◽  
I. Sarriés

The present work studies the effect the solution heat treatment, during artificial ageing and re-aging, has on the mechanical properties of an A357 aluminium alloy component formed by New Rheocasting. The effect that the evolution of silicon, during the solution treatment at various times, has on the mechanical properties was also examined. The mechanical properties were evaluated performing tensile tests, fractographical analysis and hardness tests. The microstructural characterization was made using optical and electronic microscopy.


Author(s):  
C. Saib ◽  
M. Zaoui ◽  
N. Menasri ◽  
S. Amroune ◽  
H. Ghouss

The effect of a pre (before) and post (after) heating welding treatment on the microstructure and mechanical properties of the scrap blades made of cast INC738LC superalloy is the main goal of the present investigation. The filler used in TIG welding was a INC 625 solution hardened superalloy as the proposed solution for hot cracking of the INC738LC cast superalloy in literature. The TIG welding was processed with respect to the constantly optimized parameters (current, voltage, speed, gas flux rate and number of passes) to make a mechanical properties comparison between the as received superalloy and the welded superalloy with heat treated specimens. The characterization techniques employed in this study are hardness measurements, tensile tests, optical microscopy and scanning electron microscopy. We found that the proposed preheating improves the TIG welding of the INC 738 LC superalloy specimens and the post welding heat treatment enhances its mechanical properties.


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