Effect of solution treatment temperature on microstructure evolution and tensile property of a medium Mn steel having a lamellar structure

Microstructural changes occurring in biomedical Co-Cr-Mo alloys with three carbon levels due to solution treatment and aging were investigated. Ingots of Co-Cr-Mo alloys with three different carbon levels were prepared by vacuum furnace melting; their chemical composition was Co-28Cr-6Mo-xC (x = 0.12, 0.25 and 0.35 mass%). Precipitates were electrolytically extracted from as-cast and heat-treated alloys. An M23C6 type carbide and a phase were detected as precipitates in as-cast Co-28Cr-6Mo-0.12C alloy, and an M23C6 type carbide and an  phase (M6C-M12C type carbide) were detected in as-cast Co-28Cr-6Mo-0.25C and Co-28Cr-6Mo-0.35C alloys. Only the M23C6 type carbide was detected during solution treatment. Complete precipitate dissolution occurred in all the three alloys after solution treatment. The holding time required for complete precipitate dissolution increased with increasing carbon content and decreasing solution treatment temperature. Complete precipitate dissolution occurred in the Co-Cr-Mo-C alloys solution treated at 1523 K for 43.2 ks; they were then subjected to aging from 873 to 1473 K for a heating time up to 44.1 ks after complete precipitate dissolution in solution treatment at 1523 K for 43.2 ks. The M23C6 type carbide with a grain size of 0.1–3 m was observed after aging. A time-temperature-precipitation diagram of the M23C6 type carbide formed in the Co-28Cr-6Mo-0.25C alloy was plotted.

Download Full-text

Influence of Solution Treatment Temperature on Various Properties of 21-4N Steel

DENKI-SEIKO ◽

10.4262/denkiseiko.41.294 ◽

1970 ◽

Vol 41 (4) ◽

pp. 294-301

Author(s):

Shôichi Fukui ◽

Susumu Isobe ◽

Hiroshi Hirayama

Keyword(s):

Solution Treatment ◽

Treatment Temperature ◽

Solution Treatment Temperature

Download Full-text

Effect of Dissolution of η′ Precipitates on Mechanical Properties of A7075-T6 Alloy

Korean Journal of Metals and Materials ◽

10.3365/kjmm.2022.60.1.83 ◽

2022 ◽

Vol 60 (1) ◽

pp. 83-93

Author(s):

Young-We Kim ◽

Yong-Hee Jo ◽

Yun-Soo Lee ◽

Hyoung-Wook Kim ◽

Je-In Lee

Keyword(s):

Mechanical Properties ◽

Yield Strength ◽

Solution Treatment ◽

Aluminum Matrix ◽

Natural Aging ◽

Aging Treatment ◽

Nucleation Site ◽

Treatment Temperature ◽

Solution Treatment Temperature ◽

Bake Hardening

The effects of dissolution of the η′ phase by solution treatment on the mechanical properties of A7075-T6 alloy were investigated. Immediately after solution treatment of the T6 sheet at 450 oC or higher, elongation significantly increased and dissolution of the η′ phase occurred. η′ is the main hardening phase. After natural-aging, GPI, which is coherent with the aluminum matrix, was formed and strength increased. When bake hardening after natural-aging was performed, the yield strength slightly increased due to partial dissolution of the GPI and re-precipitation of the η′ phase. In contrast, after solution treatment at 400 oC, there was less elongation increase due to the precipitation of the coarse η phase at grain boundaries and low dissolution of the η′ phase. In addition, when bake hardening after natural-aging was performed, the yield strength decreased due to insufficient GPI, which is the nucleation site of the η′ phase. To promote reprecipitation of the η′ phase, the solution treatment temperature was set to a level that would increase solubility. As a result, the yield strength was significantly increased through re-precipitation of a large number of fine and uniform η′ phase. In addition, to increase the effect of dissolution, a pre-aging treatment was introduced and the bake hardenability can be improved after dissolution.

Download Full-text

Theoretical Thermodynamic Analysis and Phase Analysis of AZ91D/Flyash Composites

Materials Science Forum ◽

10.4028/www.scientific.net/msf.788.604 ◽

2014 ◽

Vol 788 ◽

pp. 604-607

Author(s):

Hong Chao Chu ◽

Si Rong Yu ◽

Cui Xiang Wang ◽

Qi Lou

Keyword(s):

Free Energy ◽

Gibbs Free Energy ◽

Minimum Principle ◽

Solution Treatment ◽

Entropy Change ◽

Treatment Temperature ◽

Free Energy Change ◽

Energy Change ◽

Solution Treatment Temperature ◽

Gibbs Free Energy Change

The thermodynamic calculation is valuable for judging the feasibility of a reaction. In the present paper, the enthalpy change (∆HR), entropy change (∆SR) and Gibbs free energy change (∆GR) among various components in AZ91D Mg alloy-Cenosphere composites (FAC/AZ91D) were calculated. Through the calculation, we obtained the relationships between the Gibbs free energy changes and temperatures. The difficulty degree of every potential reaction could be directly reflected by the correlation curve between the temperature and the Gibbs free energy change. The analysis result provided the theoretical basis for the reaction temperature and the solution treatment temperature of the FAC/AZ91D system. At the same time, the analysis based on the minimum principle of the reaction free energy revealed the final components (MgO, Mg2Si and MgAl2O4), which was partially similar to the result of XRD analysis (MgO, Mg2Si and Mg17Al12).

Download Full-text

Influences of niobium and solution treatment temperature on pitting corrosion behaviour of stabilised austenitic stainless steels

Corrosion Science ◽

10.1016/j.corsci.2016.03.009 ◽

2016 ◽

Vol 108 ◽

pp. 111-124 ◽

Cited By ~ 33

Author(s):

Guanshun Bai ◽

Shanping Lu ◽

Dianzhong Li ◽

Yiyi Li

Keyword(s):

Pitting Corrosion ◽

Stainless Steels ◽

Corrosion Behaviour ◽

Solution Treatment ◽

Austenitic Stainless Steels ◽

Treatment Temperature ◽

Solution Treatment Temperature

Download Full-text

Effect of Solution Treatment Temperature on Microstructure and Mechanical Properties of Al-5.1Zn-2Mg-0.1Ti (wt. %) Produced by Squeeze Casting

Materials Science Forum ◽

10.4028/www.scientific.net/msf.939.38 ◽

2018 ◽

Vol 939 ◽

pp. 38-45 ◽

Cited By ~ 1

Author(s):

Risly Wijanarko ◽

Irene Angela ◽

Bondan Tiara Sofyan

Keyword(s):

Squeeze Casting ◽

Volume Fraction ◽

Solution Treatment ◽

Treatment Temperature ◽

Ageing Process ◽

Al Alloy ◽

Second Phase ◽

Solution Treatment Temperature ◽

Phase Volume Fraction ◽

Ti Addition

Al 7xxx alloy is a heat treatable Al alloy with superior strength. Solution treatment in precipitation hardening sequence of the alloy has an important role to dissolve second phases and bring vacancies out to form precipitates in the ageing process. Another strengthening can be done by Ti addition as grain refiner. As cast alloy by squeeze casting was homogenized at 400 °C for 4 h. Solution treatment was conducted at 220, 420, and 490 °C, followed by rapid quenching. Subsequent ageing was conducted at 130 °C for 48 h. Characterization was performed by optical microscope, SEM-EDS (Scanning Electron Microscopy – Energy Dispersive Spectroscopy), Rockwell hardness testing, XRD (X-Ray Diffraction), and STA (Simultaneous Thermal Analysis). Ti added alloy showed rounder grains, lower hardness, and more reduction in second phase volume fraction along with increasing solution treatment temperature than those in alloys without Ti addition. Otherwise, the alloy final hardness was increasing and higher after the ageing process due to higher second phase dissolution which leads to more precipitates formed.

Download Full-text