Microstructure and Phase Transformation of Super-High Pressure Mg-Li Alloy

2015 ◽  
Vol 816 ◽  
pp. 375-380 ◽  
Author(s):  
Qiu Ming Peng ◽  
Hui Fu ◽  
Yan An Wang ◽  
Hui Li
Keyword(s):  
High Pressure ◽  
Phase Transformation ◽  
Heat Treating ◽  
Dendritic Morphology ◽  
Metallic Materials ◽  
Cast Sample ◽  
Temperature Range ◽  
Electronic Distribution ◽  
Heat Treated ◽  
Dislocation Movement

Super-high pressure (SHP) changes crystal structure and electronic distribution of metallic materials, which plays an important role in properties. Herein, a duplex Mg-7%wt.Li alloy was heat-treated under SHP (2 GPa) by cubic-anvil large-volume press with six rams for 2 h in the temperature range of 450~1350 °C. Microstructure, phase transformation behavior and mechanical properties were examined. Compared with the as-cast sample, the SHP samples after heat-treating from 450 °C to 750 °C under 2 GPa were composed of twinning in addition to duplex structure. Comparatively, the samples treated between 1050 °C and 1350 °C exhibit typical dendritic morphology. Phase transformation from Li3Mg7 phase or Li0.92Mg4.08 phase to Li3Mg17 phase occurred during the whole investigated temperature range, in which only the Li3Mg17 phase maintained when the temperature exceeds 1050 °C. The microhardness of the sample prepared at 750 °C under 2 GPa was 73.15HV, which is 1.5 times higher than that of the as-cast one. The improved microhardness is mainly attributed to the formation of nanosized twins during SHP treatment. These fine twins effectively prohibit the dislocation movement during deformation. It reveals the SHP is an effective approach to prepare high performation Mg alloys.

A phase transformation study in the BaO · Al2O3 · 2SiO2 (BAS)–Si3N4 system

1995 ◽  
Vol 10 (12) ◽  
pp. 3143-3148 ◽  
Author(s):  
A. Bandyopadhyay ◽  
P.B. Aswath
Keyword(s):  
Phase Transformation ◽  
Phase Transformations ◽  
Metastable Phase ◽  
Heat Treating ◽  
Intermediate Step ◽  
Hexagonal Form ◽  
Heat Treated ◽  
Different Temperatures ◽  
Barium Aluminosilicate ◽  
Transformation Study

A phase transformation study was carried out with barium aluminosilicate (BAS) forming powders (BaCO3, Al2O3, and SiO2) in a BAS-Si3N4 system. Powders were heat-treated in air at 1 atm pressure at different temperatures from 600 to 1150 °C at an interval of 50 °C to study the phase transformations during the formation of BAS. The phase transformations of α to β-Si3N4 is studied by heat-treating the powders at 1600 °C for different sintering times in a nitrogen environment at 1 atm pressure. Formation of different phases was identified by using powder x-ray diffraction. Formation of different forms of barium silicates occurs as an intermediate step between 650 and 950 °C and hexagonal BAS forms between 900 and 950 °C. The hexagonal form of BAS always forms first and persists as a metastable phase in the composites with no evidence of the monoclinic phase. An attempt made to fully transform hexagonal BAS to monoclinic BAS by using LiF as a mineralizer proved to be successful. The hexagonal form of BAS forms first when heat-treated at 1000 °C and is fully transformed to monoclinic BAS when heat-treated at 1100 °C.

Alloy Design for Enhancing the Fracture Resistance of Heat Treated High Pressure Die-Castings

2010 ◽  
Vol 654-656 ◽  
pp. 954-957 ◽  
Author(s):  
Roger N. Lumley ◽  
Maya Gershenzon ◽  
Dayalan R. Gunasegaram
Keyword(s):  
Heat Treatment ◽  
High Pressure ◽  
Fracture Resistance ◽  
Heat Treating ◽  
A380 Alloy ◽  
Conventional Aluminum Alloy ◽  
Heat Treated ◽  
Treatment Technologies ◽  
Die Castings ◽  
Dimensional Instability

Recently, heat treatment technologies have been developed by the CSIRO Light Metals Flagship in Australia that allow the 0.2% proof stress of conventional aluminum alloy high pressure diecastings (HPDC’s) to be more than doubled without encountering problems with blistering or dimensional instability [1,2]. A range of other properties may also be improved such as fatigue resistance, thermal conductivity and fracture resistance. However, the current commercial HPDC Al-Si-Cu alloys have not been developed to exploit heat treatment or to optimize these specific mechanical properties, and one potential limitation of heat treating HPDC’s is that fracture resistance may be reduced as strength is increased. The current paper presents the outcomes of a program aimed at developing highly castable, secondary Al-Si-Cu HPDC alloys which display significantly enhanced ductility and fracture resistance in both the as-cast and heat treated conditions. Kahn-type tear tests were conducted to compare the fracture resistance of the conventional A380 alloy with a selection of the newly developed compositions. A comparison has also been made with the current permanent mold cast aluminium alloys and it is shown that the new HPDC compositions typically display higher levels of both tensile properties and fracture resistance.

A Preliminary Evaluation on the Fracture Toughness of Heat Treated Aluminium High Pressure Diecastings

2008 ◽  
Vol 41-42 ◽  
pp. 141-146 ◽  
Author(s):  
Roger N. Lumley
Keyword(s):  
Heat Treatment ◽  
Fracture Toughness ◽  
High Pressure ◽  
Tensile Properties ◽  
Fracture Resistance ◽  
Heat Treating ◽  
Preliminary Evaluation ◽  
Sand Cast ◽  
Heat Treated ◽  
Die Castings

Until recently, the solution heat treatment of conventional aluminum high pressure die cast (HPDC) parts has been considered impractical because the high temperatures involved cause surface blistering and dimensional instability. Now, a new heat treatment procedure has been developed by the CSIRO Light Metals Flagship in Australia which avoids these problems and, in many cases, allows tensile properties such as 0.2% proof stress to be doubled with little change to ductility. This development has the potential to reduce costs by allowing existing HPDC parts to be re-designed to use less metal and still achieve performance requirements. One issue, however, is the possibility that heat treating die castings to increase tensile properties may have an adverse effect on fracture toughness. This paper reports preliminary results of Kahntype tear tests conducted to assess the fracture resistance of as-cast and heat treated HPDCs. Studies of the alloys A360, A380 and C380 have shown that T4 and underaged (UA) T6 tempers produce an optimal combination of fracture resistance and tear strength. Furthermore, the fracture properties compare well with permanent mold and sand cast aluminium alloys that have similar tensile properties.

Phase Transformation In Ti-6al-4v Alloys

1972 ◽  
Vol 30 ◽  
pp. 584-585
Author(s):  
Shiro Fujishiro
Keyword(s):  
Phase Transformation ◽  
Grain Boundary ◽  
Cryogenic Temperature ◽  
Β Phase ◽  
Heat Treated ◽  
Mixed Microstructure ◽  
Ductile Behavior

The Ti-6 wt.% Al-4 wt.% V commercial alloys have exhibited an improved formability at cryogenic temperature when the alloys were heat-treated prior to the tests. The author was interested in further investigating this unusual ductile behavior which may be associated with the strain-induced transformation or twinning of the a phase, enhanced at lower temperatures. The starting materials, supplied by RMI Co., Niles, Ohio were rolled mill products in the form of 40 mil sheets. The microstructure of the as-received materials contained mainly ellipsoidal α grains measuring between 1 and 5μ. The β phase formed an undefined grain boundary around the a grains. The specimens were homogenized at 1050°C for one hour, followed by aging at 500°C for two hours, and then quenched in water to produce the α/β mixed microstructure.

AMPCO 940 and AMPCO-TRODE 940

Alloy Digest ◽  
1993 ◽  
Vol 42 (3) ◽  
Keyword(s):  
Copper Alloys ◽  
Heat Treating ◽  
Resistance Welding ◽  
Chromium Alloy ◽  
Heat Treated ◽  
Association Class ◽  
Potential Applications ◽  
Minimum Requirements ◽  
Nickel Silicon ◽  
Plastic Injection

Abstract AMPCO 940 is a precipitation-hardening copper-nickel-silicon-chromium alloy developed for resistance welding and other applications now using the 1% beryllium-copper alloys. The heat-treated alloy is capable of meeting the RWMA (Resistance Welder Manufacturers Association) Class 3 minimum requirements-95,000 psi tensile strength, 90 Rockwell B hardness and 45% IACS electrical conductivity. Potential applications include resistance welding tips, wheels and fixtures. A major use is in plastic injection molding. AMPCO-TRODE 940 is used for repair welding and overlays. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as casting, forming, heat treating, machining, and joining. Filing Code: CU-434. Producer or source: Ampco Metal Inc. Originally published as Ampcoloy 940, April 1982, revised March 1993.

UNS A03560

Alloy Digest ◽  
1986 ◽  
Vol 35 (12) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
High Strength ◽  
Heat Treating ◽  
Casting Alloy ◽  
Aluminum Casting ◽  
Good Resistance ◽  
Aluminum Casting Alloy ◽  
Temperature Performance ◽  
Heat Treated

Abstract UNS No. A03560 is a heat-treatable aluminum casting alloy. Normally it is used only when heat-treated (aged) strengths are required. It is recommended for high-strength, pressure-tight castings, intricate shapes and where good resistance to corrosion is needed. Its many applications include crank cases, gear cases, oil pans, airframe fittings and instrument housings. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance and corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Al-274. Producer or source: Various aluminum companies.

SCHMELZMETALL HOVADUR CCZ

Alloy Digest ◽  
2020 ◽  
Vol 69 (9) ◽  
Keyword(s):  
Thermal Conductivity ◽  
Spot Welding ◽  
Zirconium Alloy ◽  
High Strength ◽  
Heat Treating ◽  
Softening Temperature ◽  
Aged Condition ◽  
Heat Treated ◽  
High Softening Temperature ◽  
Made In

Abstract Schmelzmetall Hovadur CCZ is a heat-treatable, copper-chromium-zirconium alloy. In the solution heat-treated and artificially aged condition, this alloy exhibits high thermal and electrical conductivity along with high strength and a high softening temperature. Hovadur CCZ evolved from CuCr1 (CW105C), a precipitation-hardenable alloy first made in the 1930s for spot welding electrodes, for which strength and hardness at temperatures up to 500 °C (930 °F), as well as good electrical and thermal conductivity, are essential. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on forming, heat treating, machining, and joining. Filing Code: Cu-912. Producer or source: Schmelzmetall AG.

FEDERATED F401.5Ni

Alloy Digest ◽  
1974 ◽  
Vol 23 (12) ◽  
Keyword(s):  
Fracture Toughness ◽  
Elevated Temperatures ◽  
High Strength ◽  
Heat Treating ◽  
Casting Alloy ◽  
Aluminum Casting ◽  
Aluminum Casting Alloy ◽  
Treated Condition ◽  
Heat Treated ◽  
Heat Treated Condition

Abstract FEDERATED F401.5Ni is a heat-treatable aluminum casting alloy with high strength and good wear resistance in the fully heat-treated condition. It is recommended for castings requiring good strength at elevated temperatures. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Al-212. Producer or source: Federated Metals Corporation, ASARCO Inc..

INDALLOY 160-190

Alloy Digest ◽  
1984 ◽  
Vol 33 (1) ◽  
Keyword(s):  
Physical Properties ◽  
Tensile Properties ◽  
Precision Measurement ◽  
Heat Treating ◽  
Spray Forming ◽  
Growth Behavior ◽  
Temperature Range

Abstract INDALLOY 160-190 is a bismth-base low-melting alloy that melts through th temperature range 160-190 F. It shrinks immediately upon solidification, grows back to zero in about one hour and then shows additional growth. This shrinkage-growth behavior makes it an ideal alloy for proof casting and precision measurement of internal dimensions. This alloy originally was developed for use by children for casting soldiers and other small objects. It performs best among the low-melting alloys for spraying in the spray forming of masks and molds and in metallizing. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on casting, heat treating, machining, and joining. Filing Code: Bi-34. Producer or source: Indium Corporation of America.

UNS A96101

Alloy Digest ◽  
1988 ◽  
Vol 37 (3) ◽  
Keyword(s):  
Electrical Conductivity ◽  
Corrosion Resistance ◽  
Shear Strength ◽  
Physical Properties ◽  
High Strength ◽  
Heat Treating ◽  
High Electrical Conductivity ◽  
Treated Condition ◽  
Heat Treated ◽  
Heat Treated Condition

Abstract UNS NO. A96101 in the heat treated condition is used primarily for enclosed bus conductor where both high strength and high electrical conductivity are desirable. This datasheet provides information on composition, physical properties, hardness, elasticity, tensile properties, and shear strength as well as fatigue. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Al-287. Producer or source: Various aluminum companies.

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