本文選題：指數(shù)梯度涂層　切入點(diǎn)：多次碰撞　出處：《表面技術(shù)》2017年06期

【摘要】：目的研究在低應(yīng)力多碰條件下,在零件表面激光熔覆制備指數(shù)分布梯度涂層的效應(yīng)。方法采用網(wǎng)格坐標(biāo)劃分法,在低應(yīng)力條件下通過(guò)對(duì)Ni基指數(shù)分布梯度熔覆層的0Cr18Ni9試件進(jìn)行多碰試驗(yàn),獲取變形數(shù)據(jù),計(jì)算獲得變形率,繪制規(guī)律曲線(xiàn)。借助工具顯微鏡,獲得碰撞前后組織金相圖。結(jié)果采用的碰撞應(yīng)力僅有115 MPa,遠(yuǎn)低于涂層材料與基體的靜壓縮屈服強(qiáng)度,但指數(shù)分布的梯度涂層發(fā)生了可測(cè)的塑性變形,第一網(wǎng)格層變形率最為明顯,達(dá)到了18.97%,第二網(wǎng)格層變形率為15.03%,靠近基體的最后一個(gè)網(wǎng)格層的變形率為0.29%,可以表明指數(shù)分布梯度涂層在低應(yīng)力多碰后的形變具有"趨表效應(yīng)"�；w的形變情況與梯度涂層的形變基本一致,從距表面6 mm處開(kāi)始,涂層與基體結(jié)合處由于有瞬間激光高溫熔覆,出現(xiàn)了應(yīng)變的突變現(xiàn)象,宏觀(guān)塑性變形增大,變形率突增到3.92%,但基體的形變總的來(lái)說(shuō)也符合"趨表效應(yīng)"。同時(shí)借助金相圖看到的晶體滑移現(xiàn)象也證實(shí)了這一點(diǎn)。結(jié)論在低應(yīng)力多碰作用后,試件表層的累積變形量最大,隨著涂層深度的增加梯度減小,表明具有"趨表效應(yīng)",同時(shí)抗多沖形變的能力顯著增強(qiáng)。
[Abstract]:Aim to study the effect of laser cladding on the surface of parts under the condition of low stress and multiple impact.Methods the grid coordinate partition method was used to obtain the deformation data, calculate the deformation rate and draw the regular curve by multi-impact test on the 0Cr18Ni9 specimen of the Ni-based exponential distribution gradient cladding coating under low stress condition.With the aid of a tool microscope, metallographic diagrams of the structures before and after collision were obtained.The results show that the impact stress is only 115 MPA, which is far lower than the static compressive yield strength of the coating material and substrate. However, the gradient coating with exponential distribution has a measurable plastic deformation, and the deformation rate of the first grid layer is the most obvious.The deformation rate of the second grid layer is 15.03, and that of the last grid layer near the substrate is 0.29, which indicates that the deformation of the gradient coating with exponential distribution has a "tendency effect" after low stress and multiple collisions.The deformation of the substrate is basically consistent with that of the gradient coating. Starting from 6 mm away from the surface, because of the transient laser cladding at the interface between the coating and the substrate, there is a sudden phenomenon of strain, and the macroscopic plastic deformation increases.The deformation rate increases to 3.92, but the deformation of the matrix also accords with the "tendency effect".At the same time, the phenomenon of crystal slip can be seen by metallography.Conclusion after low stress and multiple impact, the accumulated deformation of the surface layer of the specimen is the largest, and the gradient decreases with the increase of coating depth, which indicates that there is a "tendency effect", and the ability of resisting multi-impact deformation is obviously enhanced.
【作者單位】： 蘇州工業(yè)職業(yè)技術(shù)學(xué)院;蘇州大學(xué)激光制造技術(shù)研究所;
【基金】：國(guó)家自然科學(xué)基金(10972150) 江蘇高校品牌專(zhuān)業(yè)建設(shè)工程資助項(xiàng)目(PPZY2015B186)~~
【分類(lèi)號(hào)】：TG174.44;TN249

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