Jiaqi Pan, Xiaoshan Liu, Guoqiu He, Bin Ge, Peiwen Le, Jingquan Li and Zhiqiang Zhou
The purpose of this paper is to understand the effect of particle content, applied load and sliding speed on the tribological properties of A356-SiCP composites manufactured using…
Abstract
Purpose
The purpose of this paper is to understand the effect of particle content, applied load and sliding speed on the tribological properties of A356-SiCP composites manufactured using a newly developed vacuum stir casting technique.
Design/methodology/approach
A356 alloy reinforced with 10, 15 and 20 vol% SiC particles was prepared by vacuum stir casting. Tribological tests were carried out on block-on-ring tribometer under dry sliding conditions, room temperature. Wear mechanism was investigated by scanning electron microscope and energy dispersion spectrum.
Findings
SiCP is homogeneously dispersed in the matrix. The increase in SiCP content decrease wear rate, but it leads to an increase in coefficient of friction. The wear rate increase and friction coefficient present different variation trends with increasing load. For A356-20%SiCP composite, when the load is less than 10 MPa, wear rate and friction coefficient under sliding speed of 400 rpm are lower than those of 200 rpm. Wear mechanism transition from abrasion, oxidation, delamination, adhesion to plastic flow as load and sliding speed increasing.
Practical implications
Results of this study will help guide the use of A356-SiCP in many automotive products such as brake rotors, brake pads, brake drums and pistons.
Originality/value
There are few paper studies the effect of particle content, applied load and sliding speed on the tribological properties of A356-SiCP composites. Aluminum matrix composites with uniform distribution of reinforcing particles were successfully prepared by using the newly developed vacuum stir casting technique.
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This paper aims to make a comprehensive evaluation of the progress and achievements made by China and Japan in literature collection, publication and academic research of South…
Abstract
Purpose
This paper aims to make a comprehensive evaluation of the progress and achievements made by China and Japan in literature collection, publication and academic research of South Manchuria Railways Co (SMR) after the Second World War and points out the existing and urgent problems.
Design/methodology/approach
This paper adopts the methods of literature research, questionnaire survey, comparative analysis and expert consultation.
Findings
After the Second World War, both China and Japan made great achievements in the collection, publication and research of SMR data, as well as in the academic research of SMR. However, as a new research field, there are still some problems in deepening the excavation and utilization of SMR data, expanding the research fields, improving the research methods, etc.
Originality/value
SMR itself was the product of a war of aggression. Although it died with the defeat of the war of aggression, remaining SMR data also has very precious value, it records the history of Japanese aggression against China, is the biggest database for the study of the problems in China and northeast Aisa at that time. In addition to Japan and China, the USA and the Soviet Union also kept part of the SMR data, so that to involve them in the research of SMR is also the purpose of this paper.
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For a thermal protection system (TPS) of long endurance hypersonic flight vehicle (HFV), its thermal insulation property not only determines by the manufactured morphology but…
Abstract
Purpose
For a thermal protection system (TPS) of long endurance hypersonic flight vehicle (HFV), its thermal insulation property not only determines by the manufactured morphology but also changes along time. A thermal conductivity prediction model for aerogel considering heat treatment effect is carried out and applied to solve the heat conduction problem of a TPS. The aim of this study is to provide theoretical and numerical references for further development of aerogels applying to TPSs.
Design/methodology/approach
A thermal conductivity prediction model for aerogel is established considering treatment effect. The heat conduction problem of a TPS is derived and solved by combining the differential quadrature method and the Runge–Kutta method. The prediction results of aerogel thermal conductivities are verified by comparing with those in literature, while the calculated temperature field of TPS is verified by comparing with that by ABAQUS.
Findings
Numerical results show that when applying the current prediction model, the calculated high temperature area in the aerogel layer is narrowed due to the decrease of the thermal conductivity during heat treatment process.
Originality/value
This study will be beneficial to carry out the precise design of TPS for long endurance HFVs.