本文選題：離子鍍術(shù) + 電數(shù)�。� 參考：《西安理工大學(xué)》2017年碩士論文

【摘要】：針對離子鍍技術(shù)沉積鍍層過程中基體溫度持續(xù)升高這一客觀事實(shí),本文提出以金屬熱處理中淬-回火轉(zhuǎn)變的理論為基礎(chǔ),對基體溫升和沿基體縱深方向的溫度分布進(jìn)行表征。通過改變電場環(huán)境和電源供給模式,在淬火態(tài)GCr15、淬火態(tài)40CrNiMoA基體上沉積純金屬Ti鍍層,討論電參數(shù)對基體溫升和溫度分布的影響,并進(jìn)一步考察鍍層組織和性能的變化,探尋不同鋼質(zhì)基體承載能力和鍍層組織結(jié)構(gòu)的良好配合。研究結(jié)果表明:同一靶功率密度下,基體沿縱深方向的溫度分布先直線減小,然后緩慢減小,最后保持不變。隨著靶功率密度的提高,基體沿縱深方向的溫度整體升高,基體溫升極限逐漸增大,GCr15基體由160 ℃增大到441 ℃,40CrNiMoA基體由305 ℃增大到526 ℃。同時(shí),靶功率密度增大,與基體溫升綜合作用,使得鍍層晶化程度增強(qiáng),擇優(yōu)取向由(100)晶面轉(zhuǎn)變?yōu)?110)晶面,平均晶粒尺寸由9.3 nm顯著增大到22.5 nm,表面平整度先增大后減小,且鍍層內(nèi)應(yīng)力為壓應(yīng)力,在基體溫升極限大于300 ℃之后隨著晶格微觀缺陷的消除而松弛。對于回火溫度高的40CrNiMoA基體,直流電場環(huán)境下,靶功率密度為97.50W/cm2(靶電流為7.5A)時(shí),未出現(xiàn)基體軟化,且此時(shí),氣體放電處于輝弧過渡區(qū)間,鍍層平均晶粒尺寸增大受到抑制,致密度較高,表面粗糙度最小,因而實(shí)現(xiàn)了基體承載能力和鍍層組織結(jié)構(gòu)的良好配合,并且由于內(nèi)應(yīng)力的松弛,此時(shí)沉積速率可達(dá)42.56nm/min;對于具有低回火溫度的GCr15基體,直流電場環(huán)境下,靶功率密度低至11.89 W/cm2,恰好避免基體軟化,脈沖電場環(huán)境下,脈沖峰值電流15 A、脈寬2 ms、脈沖頻率50 Hz時(shí),實(shí)現(xiàn)了對基體溫升的有效控制,同時(shí),鍍層顆粒細(xì)小、光滑平整、致密度較好,且硬度5.9 GPa、塑性指數(shù)0.670,均呈現(xiàn)較高水平,結(jié)合強(qiáng)度滿足要求,達(dá)到了工藝設(shè)計(jì)的目的。
[Abstract]:In view of the objective fact that the substrate temperature increases continuously during the deposition of the coating by ion plating, the temperature rise of the substrate and the temperature distribution along the depth of the substrate are characterized on the basis of the theory of quenching and tempering transition in metal heat treatment.By changing the electric field environment and power supply mode, pure Ti coating was deposited on quenched GCr15 and quenched 40CrNiMoA substrates. The effect of electrical parameters on the temperature rise and temperature distribution of the substrate was discussed, and the microstructure and properties of the coating were further investigated.To explore the different steel substrate bearing capacity and coating structure of good cooperation.The results show that at the same power density, the temperature distribution of the matrix along the depth decreases in a straight line, then slowly decreases, and finally remains unchanged.With the increase of the power density of the target, the temperature of the matrix along the depth direction increases as a whole, and the temperature rise limit of the matrix increases gradually from 160 鈩，

本文編號：1734265