發(fā)布時(shí)間：2018-05-21 03:16

  本文選題：電極合金 + Cu-Cr-Zr-Co-Si合金��； 參考：《南昌航空大學(xué)》2017年碩士論文

【摘要】：本文在傳統(tǒng)點(diǎn)焊電極制備工藝下,向Cu-0.8Cr-0.15Zr合金添加少量Co、Si、Y元素,以期通過多元復(fù)合強(qiáng)化方法提高銅鉻鋯點(diǎn)焊電極的綜合性能。實(shí)驗(yàn)采用金相顯微鏡、掃描電鏡、能譜分析儀、X射線衍射儀等材料研究方法,系統(tǒng)的研究了合金元素添加(Co、Si、Y)、合金元素含量(Co、Si)、合金元素比例(Co/Si)及多級時(shí)效處理對銅鉻鋯合金組織和性能的影響規(guī)律。主要得到以下研究結(jié)果:1.添加Co、Si、Y元素后合金晶粒細(xì)化,鑄態(tài)顯微組織為細(xì)小的等軸晶粒,基體內(nèi)彌散分布著大量的Co5Cr3Si2相和Co、Si組成的灰色析出相,析出相有明顯的偏聚。固溶處理后,灰色析出相完全溶解,但Co5Cr3Si2相并未溶解且有所長大。隨固溶溫度上升,合金導(dǎo)電率均快速下降,硬度值快速提高。2.時(shí)效階段,晶界處及晶粒內(nèi)部出現(xiàn)細(xì)小的析出相顆粒,隨著時(shí)效時(shí)間的延長,析出相顆粒逐漸增多,且Co5Cr3Si2相逐漸粗化。時(shí)效后期,基體中未檢測出Cr元素,且出現(xiàn)了由Co、Zr、Cr、Si元素組成的析出相。析出相主要有Co5Cr3Si2相、Co2Si相、CoZrCrSi相。導(dǎo)電率初期快速上升,后期上升趨勢減緩保持平穩(wěn)。時(shí)效溫度越高,導(dǎo)電率達(dá)到峰值時(shí)間越短。各合金均在450℃或500℃時(shí)效時(shí)硬度達(dá)到最大值,且500℃時(shí)效后期、550℃時(shí)效中后期合金硬度快速下降。3.添加Co、Si元素后,時(shí)效態(tài)導(dǎo)電率下降35-40%IACS;硬度值上升30-48HV;添加稀土元素Y后,合金導(dǎo)電率上升2-3.5%IACS;硬度值小幅上升4-30HV;添加合金元素后,合金高溫力學(xué)性能增強(qiáng)。抗高溫軟化性能明顯提高,其軟化溫度高達(dá)686℃。4.隨Co/Si元素比例增大,合金硬度、導(dǎo)電率大小順序始終保持:(Co/Si=5)(Co/Si=4)(Co/Si=3)。元素比例對合金硬度峰值、導(dǎo)電率峰值影響較大,分別為15-40HV、6.1-18.3%IACS。隨著合金中Co元素含量的增加,合金耐高溫軟化性能下降。5.保持Co/Si=4:1比例不變,隨著Co、Si元素含量增加,合金導(dǎo)電率逐漸下降,硬度值提高。合金元素含量對導(dǎo)電率峰值的影響不大,在1-5%IACS,對合金硬度峰值影響有限,只有6-10HV。且隨著合金元素添加量增多,合金耐高溫軟化性能下降。6.合金經(jīng)200℃x2h預(yù)時(shí)效處理后,合金顯微組織變化不大,導(dǎo)電率、硬度較固溶態(tài)均略有升高。固溶+200℃x2h預(yù)時(shí)效+時(shí)效處理后,合金組織大小均勻,晶粒有所粗化,析出相顆粒增多,合金導(dǎo)電率、硬度峰值分別提高3.5%IACS、8.3HV,但合金耐高溫軟化性能下降。
[Abstract]:In this paper, in order to improve the comprehensive properties of copper-chromium-zirconium spot welding electrode, a small amount of Co-Si-Y element was added to Cu-0.8Cr-0.15Zr alloy under the traditional spot welding electrode preparation process. The experiments were carried out by means of metallographic microscope, scanning electron microscope, energy dispersive analyzer and X-ray diffractometer. The effects of alloy elements on the microstructure and properties of copper-chromium-zirconium alloy were systematically studied. The main results are as follows: 1: 1. After the addition of Co-Si-Y element, the grain size of the alloy is fine, the as-cast microstructure is a fine equiaxed grain, a large number of Co5Cr3Si2 phases and gray precipitated phases composed of Co-Si are distributed in the base, and the precipitates have obvious segregation. After solid solution treatment, the gray precipitated phase was completely dissolved, but the Co5Cr3Si2 phase was not dissolved and grew up. With the increase of solution temperature, the conductivity and hardness of the alloy decreased rapidly. At the aging stage, fine precipitates appeared at grain boundaries and inside the grains. With the prolongation of aging time, the precipitates gradually increased and the Co5Cr3Si2 phase coarsened gradually. In the later stage of aging, no Cr element was detected in the matrix, and a precipitated phase composed of the element Co-ZrZrCr-Si was found in the matrix. The precipitated phase mainly consists of Co5Cr3Si2 phase, Co 2Si phase and CoZrCrSi phase. The conductivity increases rapidly at the beginning of the year, and keeps steady at the later stage. The higher the aging temperature, the shorter the peak time of conductivity. The hardness of each alloy reached the maximum value at 450 鈩，

本文編號：1917497