發(fā)布時(shí)間：2018-03-15 01:27

  本文選題：高溫　切入點(diǎn)：高速　出處：《河南科技大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：鎢銅復(fù)合材料因其高硬度、高強(qiáng)度、導(dǎo)熱導(dǎo)電性好等優(yōu)良性能被用作電磁炮導(dǎo)軌材料及高壓開(kāi)關(guān)觸頭材料。在實(shí)際使用過(guò)程中,材料常常處于熱、力、電多場(chǎng)耦合的嚴(yán)酷工況下,服役條件下材料的力學(xué)性能及微觀組織演變直接關(guān)系到零件的使用壽命和服役安全性。以往研究集中在鎢銅材料的制備和導(dǎo)電等性能上,而對(duì)于鎢銅材料的摩擦磨損行為鮮有關(guān)注,基于此,本文選用W-20Cu復(fù)合材料分別與45鋼和7075Al進(jìn)行配副,系統(tǒng)研究了高溫、高速干摩擦條件下鎢銅復(fù)合材料及配副材料的摩擦磨損行為、機(jī)理及組織演變。本文首先分析了高速條件下,不同退火態(tài)鎢銅材料摩擦磨損性能及其行為。結(jié)果發(fā)現(xiàn),在750~950℃溫度范圍內(nèi),當(dāng)保溫時(shí)間為1 h時(shí),隨著退火溫度的升高,鎢銅復(fù)合材料的導(dǎo)電率、硬度和密度變化趨勢(shì)相同,均先升高再下降。當(dāng)退火溫度分別為800℃和900℃時(shí),隨著保溫時(shí)間的延長(zhǎng),硬度先升高后降低,導(dǎo)電率降低。800℃×0.5 h時(shí)導(dǎo)電率達(dá)到峰值,為47.32%IACS。900℃×1 h時(shí)硬度達(dá)到峰值,為285 HB。退火處理后W-20Cu/45鋼摩擦系數(shù)以及鎢銅材料的磨損率與處理前相比均有所降低。W-20Cu/45鋼硬度差值在60~90 HB時(shí),摩擦系數(shù)較低,最低值為0.09。不同退火態(tài)W-20Cu/45鋼磨損機(jī)制為氧化磨損和粘著磨損。在溫度50~300℃內(nèi),選擇W-20Cu復(fù)合材料與45鋼對(duì)磨,隨環(huán)境溫度的升高,摩擦系數(shù)先升高再下降,溫度超過(guò)200℃鎢銅材料磨損率劇烈上升。分析表明,速度100 r/min時(shí),W-20Cu/45鋼磨損機(jī)制主要為磨粒磨損和氧化磨損。當(dāng)速度超過(guò)100 r/min時(shí),W-20Cu/45鋼磨損機(jī)制主要為疲勞磨損、磨粒磨損和氧化磨損。在室溫環(huán)境下,載荷400~800 N范圍內(nèi),隨著載荷升高,對(duì)磨盤(pán)45鋼磨損率變化不大,鎢銅材料磨損率劇烈上升,產(chǎn)生大量片狀磨屑。W-20Cu/45鋼摩擦系數(shù)隨著載荷的升高而升高。在重載條件下,W-20Cu/45鋼磨損機(jī)制為磨粒磨損、剝落磨損為主,粘著磨損為輔。高速滑塊式摩擦磨損試驗(yàn)?zāi)Σ了俣葹?6~57 m/s,試驗(yàn)結(jié)果表明,在高速環(huán)境下,W-20Cu/45鋼磨損機(jī)制和W-20Cu/7075Al磨損機(jī)制均為粘著磨損和磨粒磨損。隨著摩擦速度增加,W-20Cu/45鋼和W-20Cu/7075Al的摩擦系數(shù)均是隨著滑動(dòng)速度的升高而降低,鎢銅材料的磨損率隨滑動(dòng)的速度增高而降低。
[Abstract]:Tungsten and copper composites are used as materials for electromagnetic gun rails and high voltage switch contacts because of their high hardness, high strength and good thermal conductivity. The mechanical properties and microstructure evolution of materials in service are directly related to the service life and safety of parts under the harsh condition of electric-multi-field coupling. Previous studies focused on the preparation and conductive properties of tungsten and copper materials. However, little attention has been paid to the friction and wear behavior of tungsten and copper materials. Based on this, W-20Cu composite was used to match with 45 steel and 7075Al respectively, and the high temperature was studied systematically. The friction and wear behavior, mechanism and microstructure evolution of tungsten and copper composites and matching materials under high speed and dry friction conditions are analyzed in this paper. The friction and wear properties and behaviors of different annealed tungsten copper materials at high speed are analyzed. In the range of 750 ~ 950 鈩，

本文編號(hào)：1613834