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

【摘要】：鎢銅復合材料因其高硬度、高強度、導熱導電性好等優(yōu)良性能被用作電磁炮導軌材料及高壓開關觸頭材料。在實際使用過程中,材料常常處于熱、力、電多場耦合的嚴酷工況下,服役條件下材料的力學性能及微觀組織演變直接關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電等性能上,而對于鎢銅材料的摩擦磨損行為鮮有關注,基于此,本文選用W-20Cu復合材料分別與45鋼和7075Al進行配副,系統(tǒng)研究了高溫、高速干摩擦條件下鎢銅復合材料及配副材料的摩擦磨損行為、機理及組織演變。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。結果發(fā)現(xiàn),在750~950℃溫度范圍內,當保溫時間為1 h時,隨著退火溫度的升高,鎢銅復合材料的導電率、硬度和密度變化趨勢相同,均先升高再下降。當退火溫度分別為800℃和900℃時,隨著保溫時間的延長,硬度先升高后降低,導電率降低。800℃×0.5 h時導電率達到峰值,為47.32%IACS。900℃×1 h時硬度達到峰值,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,摩擦系數(shù)較低,最低值為0.09。不同退火態(tài)W-20Cu/45鋼磨損機制為氧化磨損和粘著磨損。在溫度50~300℃內,選擇W-20Cu復合材料與45鋼對磨,隨環(huán)境溫度的升高,摩擦系數(shù)先升高再下降,溫度超過200℃鎢銅材料磨損率劇烈上升。分析表明,速度100 r/min時,W-20Cu/45鋼磨損機制主要為磨粒磨損和氧化磨損。當速度超過100 r/min時,W-20Cu/45鋼磨損機制主要為疲勞磨損、磨粒磨損和氧化磨損。在室溫環(huán)境下,載荷400~800 N范圍內,隨著載荷升高,對磨盤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摩擦速度為26~57 m/s,試驗結果表明,在高速環(huán)境下,W-20Cu/45鋼磨損機制和W-20Cu/7075Al磨損機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)均是隨著滑動速度的升高而降低,鎢銅材料的磨損率隨滑動的速度增高而降低。
[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：1613834