scholarly journals Effects of Solidification Cooling Rate on the Microstructure and Mechanical Properties of a Cast Al-Si-Cu-Mg-Ni Piston Alloy

Materials ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1230 ◽  
Author(s):  
Lusha Tian ◽  
Yongchun Guo ◽  
Jianping Li ◽  
Feng Xia ◽  
Minxian Liang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cooling Rate ◽  
Eutectic Silicon ◽  
Model Alloy ◽  
Chinese Script ◽  
Uniform Structure ◽  
Elongation At Break ◽  
Piston Alloy ◽  
Δ Phase ◽  
Al3ni Phase

The effects of cooling rate 0.15, 1.5, 15, 150, and 1.5 × 105 °C/s on the microstructures and mechanical properties of Al-13Si-4Cu-1Mg-2Ni cast piston alloy were investigated. The results show that with an increase of solidification cooling rate, the secondary dendrite arm spacing (SDAS) of this model alloy can be calculated using the formula D = 47.126v − 1/3. The phases formed during the solidification with lower cooling rates primarily consist of eutectic silicon, M-Mg2Si phase, γ-Al7Cu4Ni phase, δ-Al3CuNi phase, ε-Al3Ni phase, and Q-Al5Cu2Mg8Si6 phase. With the increase in the solidification cooling rate from 0.15 to 15 °C/s, the hardness increased from 80.9 to 125.7 HB, the room temperature tensile strength enhanced from 189.3 to 282.5 MPa, and the elongation at break increased from 1.6% to 2.8%. The ε -Al3Ni phase disappears in the alloy and the Q phase emerges. The δ phase and the γ phase change from large-sized meshes and clusters to smaller meshes and Chinese script patterns. Further increase in the cooling rate leads to the micro hardness increasing gradually from 131.2 to 195.6 HV and the alloy solidifying into a uniform structure and forming nanocrystals.

scholarly journals Preparation and Characteristic of PC/PLA/TPU Blends by Reactive Extrusion

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Yueyun Zhou ◽  
Lifa Luo ◽  
Wenyong Liu ◽  
Guangsheng Zeng ◽  
Yi Chen
Keyword(s):  
Mechanical Properties ◽  
Fracture Behavior ◽  
Reactive Extrusion ◽  
Uniform Structure ◽  
Intrinsic Properties ◽  
Elongation At Break ◽  
The Poor ◽  
Properties Of Materials ◽  
The Impact ◽  
Thermal Stability Of

To overcome the poor toughness of PC/PLA blends due to the intrinsic properties of materials and poor compatibility, thermoplastic urethane (TPU) was added to PC/PLA blends as a toughener; meantime, catalyst di-n-butyltin oxide (DBTO) was also added for catalyzing transesterification of components in order to modify the compatibility of blends. The mechanical, thermal, and rheological properties of blends were investigated systematically. The results showed that the addition of TPU improves the toughness of PC/PLA blends significantly, with the increase of TPU, the elongation at break increases considerably, and the impact strength increases firstly and then falls, while the tensile strength decreases significantly and the blends exhibit a typical plastic fracture behavior. Meantime, TPU is conducive to the crystallinity of PLA in blends which is inhibited seriously by PC and damages the thermal stability of blends slightly. Moreover, the increased TPU makes the apparent viscosity of blends melt decrease due to the well melt fluidity of TPU; the melt is closer to the pseudoplasticity melt. Remarkably, the transesterification between the components improves the compatibility of blends significantly, and more uniform structure results in a higher crystallinity and better mechanical properties.

scholarly journals Influence of cooling rate on microstructure development of AlSi9MgMn alloy

2020 ◽  
pp. 36-36
Author(s):  
Davor Stanic ◽  
Zdenka Zovko-Brodarac
Keyword(s):  
Mechanical Properties ◽  
Cooling Rate ◽  
Eutectic Reaction ◽  
Primary Dendrite ◽  
Manganese Content ◽  
Thermal Analyses ◽  
Chinese Script ◽  
Dendrite Network ◽  
3Si2 Phase

Aluminum alloys are widely applied in automotive, aircraft, food and building industries. Multicomponent technical AlSi9MgMn alloy is primarily intended for high cooling rate technology. Controlled addition of alloying elements such as iron and manganese as well as magnesium can improve mechanical and technological properties of final casting in dependence from cooling conditions during solidification. The aim of this investigation is characterization of AlSi9MgMn alloy microstructure and mechanical properties at lower cooling rates than those for which this alloy was primarily developed. Thermodynamic calculation and thermal analyses revealed solidification sequence in correlation to microstructure investigation as follows: development of primary dendrite network, precipitation of high temperature Al15(Mn,Fe)3Si2 and Al5FeSi phases, main eutectic reaction, precipitation of intermetallic Al8Mg3FeSi6 phase and Mg2Si as a final solidifying phase. Influence of microstructure features investigation and cooling rate reveals significant Al15(Mn,Fe)3Si2 morphology change from Chinese script morphology at low, irregular broken Chinese script morphology at medium and globular morphology at high cooling rate. High manganese content in AlSi9MgMn alloy together with high cooling rate enables increase of Fe+Mn total amount in intermetallic Al15(Mn,Fe)3Si2 phase and encourage favourable morphology development, all resulting in enhanced mechanical properties in as-cast state.

Effect of Compound Modification and Cooling Rate on Microstructure and Mechanical Properties of Al-25%Si Alloy

2016 ◽  
Vol 877 ◽  
pp. 27-32
Author(s):  
Hai Tao Zhang ◽  
Dong Tao Wang ◽  
Ke Qin ◽  
Xing Han ◽  
Bo Shao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cooling Rate ◽  
Mechanical Testing ◽  
Rate Increase ◽  
Eutectic Silicon ◽  
Primary Silicon ◽  
Microstructure And Mechanical Properties ◽  
Phosphorus Modification ◽  
Compound Modification

The effect of phosphorus on primary silicon, phosphorus and mischmetal (Ce-50La) modification on primary and eutectic silicon and cooling rate on microstructure of Al-25%Si are investigated. The results show that, with the addition of phosphorus, the size of primary silicon decreases from 93.6μm to 24.75μm. The morphology of primary silicon changes from irregular to polygonal. When Al-25%Si is modified by phosphorus and mischmetal, primary and eutectic silicon all change effectively. Addition of mischmetal on the basis of phosphorus modification have no influence to primary silicon, but it can make morphology of eutectic silicon change from lamellar to short rod-like when the content of mischmetal reaches 0.5%. The cooling rate curves show the change of temperature in different height of wedge-shaped mould. When cooling rate increases, microstructure of Al-25%Si refines, the size of primary silicon decrease to 22.7μm. The results obtained from mechanical testing demonstrate that the addition of mischmetal and increasing of cooling rate increase hardness value of Al-25%Si alloy.

Effect of Casting Size on Microstructure and Mechanical Properties of Thixocastings

2014 ◽  
Vol 217-218 ◽  
pp. 45-52
Author(s):  
Hong Xing Lu ◽  
Qiang Zhu ◽  
You Feng He ◽  
Da Quan Li ◽  
Stephen P. Midson
Keyword(s):  
Mechanical Properties ◽  
Cooling Rate ◽  
Eutectic Silicon ◽  
General Rule ◽  
Metal Casting ◽  
Casting Section ◽  
Microstructure And Mechanical Properties ◽  
Section Size ◽  
Semi Solid ◽  
The Impact

A general rule in conventional liquid metal casting processes is that smaller size would produce better metallurgical quality and mechanical properties. The conclusion that semi-solid thixocasting process doesnt follow this rule has been made recently. The microstructure and mechanical properties of semi-solid thixocastings are much less dependent on casting size and cooling rate than the liquid castings. The step casting in the previous study is specially designed and simplified. The practical castings, e.g. turbocharger impellers, are more complex than the step castings. In this work, the turbocharger impeller is used to study the impact of section size representing the casting size on the microstructure and mechanical properties of semi-solid thixocastings, compared with the step casting. Section thickness decreases from 50 mm to 3.5 mm. In addition, the impact of casting thickness on the eutectic phase is also presented. The results reveal that the size of primary α-Al particles is insensitive to the casting thickness in semi-solid thixocasting. The cooling rate has a notable impact on the size and geometric characteristics of the eutectic silicon particles, but the impact is reduced by the following T61 heat treatment. The association between the casting thickness and casting defects is discussed, in order to further understand the impact of casting size on durability and reliability of real casting components.

Effects of cooling rate on the mechanical properties of dual phase treated vanadium steels

1983 ◽  
Vol 41 ◽  
pp. 220-221
Author(s):  
L.J. Chen ◽  
H.C. Cheng ◽  
J.R. Gong ◽  
J.G. Yang
Keyword(s):  
Mechanical Properties ◽  
Cooling Rate ◽  
Automobile Industry ◽  
High Strength ◽  
Weight Percent ◽  
Low Alloy Steels ◽  
Dual Phase ◽  
Resource Requirement ◽  
Alloy Steels ◽  
Potential Weight

For fuel savings as well as energy and resource requirement, high strength low alloy steels (HSLA) are of particular interest to automobile industry because of the potential weight reduction which can be achieved by using thinner section of these steels to carry the same load and thus to improve the fuel mileage. Dual phase treatment has been utilized to obtain superior strength and ductility combinations compared to the HSLA of identical composition. Recently, cooling rate following heat treatment was found to be important to the tensile properties of the dual phase steels. In this paper, we report the results of the investigation of cooling rate on the microstructures and mechanical properties of several vanadium HSLA steels.The steels with composition (in weight percent) listed below were supplied by China Steel Corporation: 1. low V steel (0.11C, 0.65Si, 1.63Mn, 0.015P, 0.008S, 0.084Aℓ, 0.004V), 2. 0.059V steel (0.13C, 0.62S1, 1.59Mn, 0.012P, 0.008S, 0.065Aℓ, 0.059V), 3. 0.10V steel (0.11C, 0.58Si, 1.58Mn, 0.017P, 0.008S, 0.068Aℓ, 0.10V).

scholarly journals Effect of Organic Modifier Types on the Physical–Mechanical Properties and Overall Migration of Post-Consumer Polypropylene/Clay Nanocomposites for Food Packaging

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1502
Author(s):  
Eliezer Velásquez ◽  
Sebastián Espinoza ◽  
Ximena Valenzuela ◽  
Luan Garrido ◽  
María José Galotto ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Food Packaging ◽  
Clay Nanocomposites ◽  
Organic Modifier ◽  
Thermal And Mechanical Properties ◽  
Chemical Safety ◽  
Elongation At Break ◽  
Fatty Food ◽  
Recycled Plastics ◽  
Thermal Stability Of

The deterioration of the physical–mechanical properties and loss of the chemical safety of plastics after consumption are topics of concern for food packaging applications. Incorporating nanoclays is an alternative to improve the performance of recycled plastics. However, properties and overall migration from polymer/clay nanocomposites to food require to be evaluated case-by-case. This work aimed to investigate the effect of organic modifier types of clays on the structural, thermal and mechanical properties and the overall migration of nanocomposites based on 50/50 virgin and recycled post-consumer polypropylene blend (VPP/RPP) and organoclays for food packaging applications. The clay with the most hydrophobic organic modifier caused higher thermal stability of the nanocomposites and greater intercalation of polypropylene between clay mineral layers but increased the overall migration to a fatty food simulant. This migration value was higher from the 50/50 VPP/RPP film than from VPP. Nonetheless, clays reduced the migration and even more when the clay had greater hydrophilicity because of lower interactions between the nanocomposite and the fatty simulant. Conversely, nanocomposites and VPP/RPP control films exhibited low migration values in the acid and non-acid food simulants. Regarding tensile parameters, elongation at break values of PP film significantly increased with RPP addition, but the incorporation of organoclays reduced its ductility to values closer to the VPP.

scholarly journals Low-Temperature Mechanical Properties of High-Density and Low-Density Polyethylene and Their Blends

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1821
Author(s):  
Ildar I. Salakhov ◽  
Nadim M. Shaidullin ◽  
Anatoly E. Chalykh ◽  
Mikhail A. Matsko ◽  
Alexey V. Shapagin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Low Temperature ◽  
Impact Strength ◽  
Relative Elongation ◽  
High Density ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Elongation At Break ◽  
Subzero Temperatures ◽  
Izod Impact

Low-temperature properties of high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and their blends were studied. The analyzed low-temperature mechanical properties involve the deformation resistance and impact strength characteristics. HDPE is a bimodal ethylene/1-hexene copolymer; LDPE is a branched ethylene homopolymer containing short-chain branches of different length; LLDPE is a binary ethylene/1-butene copolymer and an ethylene/1-butene/1-hexene terpolymer. The samples of copolymers and their blends were studied by gel permeation chromatography (GPC), differential scanning calorimetry (DSC), 13С NMR spectroscopy, and dynamic mechanical analysis (DMA) using testing machines equipped with a cryochamber. It is proposed that such parameters as “relative elongation at break at −45 °C” and “Izod impact strength at −40 °C” are used instead of the ductile-to-brittle transition temperature to assess frost resistance properties because these parameters are more sensitive to deformation and impact at subzero temperatures for HDPE. LLDPE is shown to exhibit higher relative elongation at break at −45 °C and Izod impact strength at −20 ÷ 60 °C compared to those of LDPE. LLDPE terpolymer added to HDPE (at a content ≥ 25 wt.%) simultaneously increases flow properties and improves tensile properties of the blend at −45 °C. Changes in low-temperature properties as a function of molecular weight, MWD, crystallinity, and branch content were determined for HDPE, LLDPE, and their blends. The DMA data prove the resulting dependences. The reported findings allow one to understand and predict mechanical properties in the HDPE–LLDPE systems at subzero temperatures.

scholarly journals The Structure and Mechanical Properties of Hemp Fibers-Reinforced Poly(ε-Caprolactone) Composites Modified by Electron Beam Irradiation

2021 ◽  
Vol 11 (12) ◽  
pp. 5317
Author(s):  
Rafał Malinowski ◽  
Aneta Raszkowska-Kaczor ◽  
Krzysztof Moraczewski ◽  
Wojciech Głuszewski ◽  
Volodymyr Krasinskyi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Electron Beam ◽  
Impact Strength ◽  
Flexural Modulus ◽  
Natural Fibers ◽  
High Energy ◽  
Electron Radiation ◽  
Elongation At Break ◽  
Hemp Fibers

The need for the development of new biodegradable materials and modification of the properties the current ones possess has essentially increased in recent years. The aim of this study was the comparison of changes occurring in poly(ε-caprolactone) (PCL) due to its modification by high-energy electron beam derived from a linear electron accelerator, as well as the addition of natural fibers in the form of cut hemp fibers. Changes to the fibers structure in the obtained composites and the geometrical surface structure of sample fractures with the use of scanning electron microscopy were investigated. Moreover, the mechanical properties were examined, including tensile strength, elongation at break, flexural modulus and impact strength of the modified PCL. It was found that PCL, modified with hemp fibers and/or electron radiation, exhibited enhanced flexural modulus but the elongation at break and impact strength decreased. Depending on the electron radiation dose and the hemp fibers content, tensile strength decreased or increased. It was also found that hemp fibers caused greater changes to the mechanical properties of PCL than electron radiation. The prepared composites exhibited uniform distribution of the dispersed phase in the polymer matrix and adequate adhesion at the interface between the two components.

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