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Study of Valent Electron Structure and Properties of CuNiSi Alloy

Author: RenWei
Tutor: JiaShuGuo
School: Henan University of Science and Technology
Course: Materials Science
Keywords: CuNiSi alloy Valence electron structure Recrystallization behavior EET theory Aging
CLC: TG111.1
Type: Master's thesis
Year: 2010
Downloads: 41
Quote: 0
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Abstract


Cu-Ni-Si alloy is a typical aging hardening alloys, the characteristics of both high strength and high electrical conductivity, compared with the currently used lead frame material is not magnetic, and thus become the ideal timber for VLSI, has broad application prospects, becoming the focus of people's studies. Based on empirical electron theory of solids and molecules (EET theory), the establishment of the electronic structure of the phase space price calculation model to calculate the pure metal crystal Cu alloys Cu-Si, Cu-Ni, Cu-Ni-Si unit cell valence electrons structure; focuses on the Cu-Ni-Si alloy conductivity, microhardness and microstructure of cold deformation and multi-step aging process as well as alloying elements Ni and Si added amount of Cu-Ni-Si alloy recrystallization behavior the impact and use of transmission electron microscopy in-depth study focuses on phase precipitates in the Cu-Ni-Si alloy during aging. The study results show that: the pure metal Cu alloy solid solution Cu-Si, Cu-Ni, Cu-Ni-Si unit cell strongest bond valence electron number were 0.375968,0.40125,0.42026,0.45722 visible alloying elements Ni and Si the crossfade can improve the the atomic bonds gravity of the pure copper unit cell, strengthen the copper matrix. EET better for Cu-Ni-Si alloy components designed to provide theoretical guidance and processing. Cold deformation before aging treatment can significantly improve the microhardness and electrical conductivity of Cu-Ni-Si alloys, such as, without cold deformation Cu-Ni-Si alloy aged at 450 ° C × 0.5h microhardness and The conductivity of 218 HV, and 32.1% IACS, after the amount of deformation of 80% of the cold deformation of the Cu-Ni-Si alloy by 450 ° C × 0.5h after aging, its micro-hardness and electrical conductivity, respectively of 242HV and 36.9% IACS , the overall performance of the alloy have been significantly improved. Multi-class combination of aging can significantly improve the overall performance of Cu-Ni-Si alloy, alloy three aging tensile strength and conductivity, respectively 701MPa and 49.3% IACS, significantly higher than the two aging 633MPa and 45.6 % IACS and much higher than the overall performance of a single aging process. The added amount of the alloying elements Ni and Si will significantly affect the recrystallization behavior of Cu-Ni-Si alloys, the alloying elements Ni and Si content of the higher recrystallization during more slowly, the higher the recrystallization temperature. TEM studies have shown that precipitation in the Cu-Ni-Si alloy during aging phase of Ni 2 Si phase with increasing aging time and aging temperature, the precipitation of Cu-Ni-Si alloy phase length big trend, so that the strength of the alloy is reduced and the conductivity is increased.

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CLC: > Industrial Technology > Metallurgy and Metal Craft > Metallurgy and Heat Treatment > Metallurgy ( Physical Metallurgy ) > Physics of metals > The electron theory of metals
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