Formability and strengthening mechanism of AA6061 tubular components under solid granule medium internal high pressure forming

To reveal the pressure-transfer characteristics of the granular materials in the Solid Granule Medium Forming process, the stainless steel balls with diameter of 1 mm were selected as medium to conduct the axial compression experiment. The particle compression process was simulated by discrete element method, and then the variation law of the microstructure was analyzed from the perspective of force chain. The results showed that: In the gradual compression process of granule medium, its force chains distribution changes from the initial circular shape to the elliptical shape. As the stress increases, the force chains get denser and denser. In addition, the lateral pressure coefficient changes in power law with the compressive stress and it tends to be constant when the internal force chains structure gets stable.

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Flexible-die forming process with solid granule medium on sheet metal

Transactions of Nonferrous Metals Society of China ◽

10.1016/s1003-6326(13)62783-1 ◽

2013 ◽

Vol 23 (9) ◽

pp. 2666-2677 ◽

Cited By ~ 28

Author(s):

Guo-jiang DONG ◽

Chang-cai ZHAO ◽

Miao-yan CAO

Keyword(s):

Sheet Metal ◽

Forming Process ◽

Flexible Die Forming ◽

Granule Medium ◽

Flexible Die ◽

Die Forming ◽

Solid Granule

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Microstructure and Mechanical Propertiesof Ti/Cu-Cr/S20C and Ti/Cu-Ag/S20C Clad Composites

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.376.153 ◽

2013 ◽

Vol 376 ◽

pp. 153-157 ◽

Cited By ~ 1

Author(s):

Jong Su Ha ◽

Sun Ig Hong

Keyword(s):

Heat Treatment ◽

High Pressure ◽

Strain Hardening ◽

Intermetallic Compounds ◽

Mechanical Performance ◽

High Strength ◽

Strengthening Mechanism ◽

Reaction Products ◽

Heat Treated ◽

Strength And Ductility

In this study Cu-Ag or Cu-Cr layer was sandwiched by Ti and Fe plates and the three layers of Ti/Cu-8Ag/S20C were clad by High Pressure Torsioning(HPT). The effect of post-HPT heat treatment on the interfacial reaction products and the mechanical performance in Ti/Cu-Ag/S20C and Ti/Cu-Cr/S20C clad material were studied. Cu4Ti3 and Cu4Ti Intremetallic compound layers were observed at the Ti/Cu-Ag and Ti/Cu-Cr interfaces in the clad heat-treated at 500°C where as no intermetallic compounds were observed at the Cu-Ag/S20C and Cu-Cr/S20C interfaces. The strength of as-HPTed Ti/Cu-8Ag/S20C is much higher than that of Ti/Cu-1Cr/S20C. The strengthening mechanism of Cu-Ag deformed severely is the interface and strain hardening in which dislocations are deposited at the Cu/Ag interfaces and can contribute to the strengthening of the clad composite just after HPT processing, rendering the high strength just after processing. In both clad composites, the strength and ductility increased after heat treatment at 350°C, which are likely caused by the enhanced bonding at the interfaces.

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Progress on High Pressure Pneumatic Forming and Warm Hydroforming of Titanium and Magnesium Alloy Tubular Components

Materials Science Forum ◽

10.4028/www.scientific.net/msf.783-786.2456 ◽

2014 ◽

Vol 783-786 ◽

pp. 2456-2461 ◽

Cited By ~ 3

Author(s):

Gang Liu ◽

Yong Wu ◽

Jian Long Wang ◽

Wen Da Zhang

Keyword(s):

High Pressure ◽

Temperature Field ◽

Magnesium Alloy ◽

Thickness Distribution ◽

Expansion Ratio ◽

Mg Alloy ◽

Ti Alloy ◽

Warm Hydroforming ◽

Corner Filling ◽

Tubular Components

Complex structural tubular components of Titanium and Magnesium alloy can be obtained at a certain temperature by high pressure pneumatic forming (HPPF) with gas medium or warm hydroforming with pressurized liquid medium. At 800°C, through experimental research on HPPF of TA18 Ti-alloy tube with expansion ratio of 50%, the influence of axial feeding on thickness distribution of the workpiece was studied. Using reasonable loading curve, the component with large ratio can be formed with a small thinning ratio as 13% with total axial feeding amount of 40mm. At 850°C, HPPF experiments of TA18 Ti-alloy component with square section were carried out. The influence of gas pressure on thickness distribution and corner filling process were analyzed. The larger the pressure, the sooner the displacement changes at the corner, and the shorter corner filling term. At pressure of 30 MPa, small corner with the relative corner radius of 2.0 can be obtained within 168s. For Mg-alloy tubular part, warm hydroforming with non-uniform temperature field was studied. By using reasonable axial temperature field and loading path, the maximum thinning ratio of Mg-alloy tubular component with expansion ratio of 35% was reduced from 21.6% to 11.6%.

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