| Summary: | 碩士 === 義守大學 === 材料科學與工程學系 === 101 === In this study, powder metallurgy process to produce with precipitation hardening (Cu-Ni-Si-Cr) and dispersion strengthening (addition Al2O3) and other dual-strengthening mechanism of Cu-Ni-Si-Cr + Al2O3 alloy and designed a series of heat treatment to optimum mechanical properties and thermal properties.
The study design of the literature and patents, respectively, and vacuum induction melting powder aerosol prepared Cu-Ni-Si-Cr alloy powder, and less Preparation of Cu-Al2O3 oxide alloy powder, the two powders according 7:3 after mixing ratio of powder sintering Cu-Ni-Si-Cr + Al2O3 composite alloy and through inductively coupled plasma - atomic emission spectroscopy (Inductively Coupled Plasma with Atomic Emission. Spectroscopy, ICP-AES) analysis confirmed that the actual composition of the alloy composition of Cu-5.11Ni-1.04Si-0.61Cr + Al2O3.
Through the literature analysis and design parameters of a series of heat treatment; heat treatment via an optical microscope (Optical microscope, OM), scanning electron microscopy (Scanning electron microscope, SEM) observations and other microstructure, micro hardness and thermal conductivity coefficients measured Definition the better the heat treatment parameters, and further heat treatment parameters for better specimen to electron probe micro analyzer (Electron probe micro-analyzer, EPMA) to do an analysis of diffusion of the components, the latter through a transmission electron microscope (Transmission electron microscopy, TEM ) for phase identification and analysis of the strengthening phase, and finally the tensile test specimens measuring mechanical properties.
Currently Cu-5.11Ni-1.04Si-0.61Cr + Al2O3 composite alloy development results show that the alloy microstructure by the Cu-Ni-Si-Cr (A grain) and Cu-Al2O3 (B grain) are composed of two grains after aging heat treatment although a grain of Ni, Si will enter through the diffusion of B grain, but a grain hardness (approximately 273Hv) B grain still more high, and is more susceptible to low hardness tensile properties of B grain (approximately 258Hv ) dominated nature of the grain, so the tensile strength of 560MPa only so, but the overall alloy numerical aspects of the thermal conductivity can be achieved 110W/m-K.
In addition, the experimental results propose a series of recommendations to improve its mechanical properties, expect the mechanical properties of the alloy can be further improved.
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