馮力，馬凱，楊偉杰，王寧，袁昱東，李文生

熱噴涂與冷噴涂技術(shù)

冷噴涂輔助原位合成CuNiCoFeCrAl2.3高熵合金涂層組織與性能研究

馮力1,2，馬凱1，楊偉杰1，王寧1，袁昱東1，李文生1,2

（1.蘭州理工大學(xué) 材料科學(xué)與工程學(xué)院，蘭州 730050；2.有色金屬先進加工與再利用國家重點實驗室，蘭州 730050）

為了提升普通金屬材料的表面耐腐蝕和耐磨性能，提出了一種在普通金屬材料表面制備性能良好的CuNiCoFeCrAl2.3高熵合金涂層的技術(shù)工藝。利用冷噴涂技術(shù)在45#鋼基體上制備混合金屬涂層，再經(jīng)過感應(yīng)重熔技術(shù)將混合金屬涂層原位合成為CuNiCoFeCrAl2.3高熵合金涂層。通過采用掃描電子顯微鏡（SEM）、X射線衍射儀（XRD）、能譜儀（EDS）、顯微硬度計、磨料磨損試驗機等，對涂層的相組成、顯微組織、硬度、耐磨性進行分析。原位合成CuNiCoFeCrAl2.3高熵合金涂層組織致密，元素均勻分布，合金涂層由簡單的BCC相構(gòu)成，涂層的微觀組織呈現(xiàn)出典型的枝晶結(jié)構(gòu)。內(nèi)枝晶區(qū)主要富含Co、Cr、Fe和Ni，枝晶間區(qū)則富含Cu和Al。CuNiCoFeCrAl2.3高熵合金涂層的顯微硬度是45#鋼基體的3倍，在干摩擦條件下，CuNiCoFeCrAl2.3高熵合金涂層在摩擦過程中以磨粒磨損為主，涂層在干滑動條件下的磨損率比45#鋼基體的磨損率低59%，摩擦因數(shù)為0.38，約為45#鋼基體的56%，CuNiCoFeCrAl2.3高熵合金涂層的磨損率為2.95×10?5mm3/(N·m)。使用冷噴涂輔助原位合成CuNiCoFeCrAl2.3高熵合金涂層具有很高的硬度和良好的耐磨性能。

高熵合金；冷噴涂；感應(yīng)重熔；微觀組織；耐磨性

2004年葉均蔚等[1]、Cantor等[2]提出一種新的合金設(shè)計的理論，稱為“多主元高熵合金”。高熵合金一般由5種或5種以上的元素按照近似等原子比或等原子比合金化后，而主要元素的原子數(shù)分數(shù)為5%～35%，次要元素的原子數(shù)分數(shù)小于5%，所得合金的混合熵高于熔化熵，形成簡單固溶體一類的合金[3]。由于高熵合金獨特的相結(jié)構(gòu)，使得高熵合金具有高強度、良好的耐磨性、高穩(wěn)定性[4-6]等優(yōu)異的性能，是具有廣泛應(yīng)用前景的涂層材料。眾多學(xué)者采用不同的方法將高熵合金制備成為涂層，并推廣應(yīng)用于不同的工業(yè)領(lǐng)域。

目前，高熵合金涂層的制備工藝包括冷噴涂激光熔覆[7]、電化學(xué)沉積[8]、磁控濺射[9]、冷噴涂[10]等。Ye等[11]通過激光熔覆法制備了AlFeCoNiCuCr高熵合金涂層，獲得了納米結(jié)構(gòu)的固溶體，研究結(jié)果表明，隨著Al元素的增加，涂層由FCC+BCC向BCC相轉(zhuǎn)變，涂層的顯微硬度也會提高。Soare等[12]通過電化學(xué)沉積法制備了AlCrFeMnNi和AlCrCuFeMnNi高熵合金涂層。涂層由球形、片狀顆粒和直徑約500 nm的顆粒簇組成。在873 K高溫下熱處理2 h可得到BCC固溶結(jié)構(gòu)，對基材有很高的附著力。但是，用這種方法制備的涂層有很多裂紋而且涂層太薄。Huang等[13]使用熱噴涂技術(shù)制備了AlCrFeMo0.5NiSiTi高熵合金涂層和AlCoCrFeMo0.5NiSiTi高熵合金涂層，涂層主要由BCC和FCC相構(gòu)成，涂層的厚度約為200 μm，合金的硬度為700～900HV。Ang等[14]通過機械合金化方法研磨制備高熵合金納米粉末，再通過等離子噴涂方法將高熵合金粉末制備成AlCoCrFeNi和MnCoCrFeNi高熵合金涂層，涂層由FCC和BCC相組成，硬度可達4.42 Gpa。冷噴涂[15-16]屬于熱噴涂技術(shù)的一種，之所以叫冷噴涂，是因為其噴涂時的氣流溫度遠低于傳統(tǒng)熱噴涂技術(shù)。冷噴涂與傳統(tǒng)熱噴涂技術(shù)相比，工作溫度低，不需要高溫氧化，涂層基體能保持材料顆粒的結(jié)構(gòu)和成分，減少材料的氧化或相變。Yin等[15]采用冷噴涂技術(shù)在45#鋼基體上用預(yù)制的高熵合金粉末成功制備了FeCoNiCrMn高熵合金涂層，由于冷噴涂的特點，涂層沒有發(fā)生相變，涂層保留了高熵合金粉末的相結(jié)構(gòu)和高熵合金優(yōu)良的力學(xué)性能。Anupam等[16]利用冷噴涂技術(shù)制備AlCoCrFeNi高熵合金涂層并研究高溫氧化機理，結(jié)果表明：在1 100 ℃的環(huán)境下，該涂層的表面形成一層氧化物可以保護基體25 h，而通過優(yōu)化工藝參數(shù)可以最大限度提高涂層質(zhì)量并提高涂層抗氧化性。冷噴涂技術(shù)制備的涂層，粉末顆粒之間存在太多的界面，降低了涂層中的附著力，因此有學(xué)者采用涂層重熔的方法，來提高冷噴涂層的性能[17]。

本文采用冷噴涂輔助原位合成的方法[18-19]制備厚度為400 μm的CuNiCoFeCrAl2.3高熵合金涂層。這種方法能有效消除冷噴涂涂層中粉末顆粒之間的界面，提高涂層的附著力與內(nèi)聚力，涂層的附著力可以達到120 Mpa。使用這種方法，不需要預(yù)制高熵合金粉末，以混合金屬單質(zhì)粉末為噴涂原料在基體上制備預(yù)制混合金屬涂層，再利用感應(yīng)重熔技術(shù)原位合成高熵合金涂層。因此，這種方法制備涂層具有制備成本低、周期短、易于調(diào)整涂層成分的優(yōu)點。

1 試驗

1.1 涂層的制備

本試驗所用原料是根據(jù)制備涂層材料要求的商用金屬單質(zhì)粉末（純度>99.5%），將金屬單質(zhì)粉末機械混合4 h后作為冷噴涂預(yù)制原料，冷噴涂原料的微觀形貌如圖1所示。圖1中Cu、Ni、Fe粉末為樹枝狀的電解粉，Al、Co粉末為球狀的霧化粉，Cr粉末為不規(guī)則形貌的破碎粉。不同的金屬粉末，在相同的冷噴涂工藝下有不同的沉積率，冷噴涂原料的各種金屬粉末含量，按照各種金屬粉末的沉積率和涂層中的元素成分比率來計算。通過試驗，得到不同金屬元素上粉率的比值，按照原子比表征為Cu∶Ni∶Co∶Cr∶Fe∶Al2.3=1.7∶1.6∶1.6∶1.4∶1.3∶1.1。最終制備的涂層的金屬元素的質(zhì)量分數(shù)見表1。基體材料選用45#鋼，噴涂前用丙酮超聲清洗基體表面的油污等雜質(zhì)，然后噴砂粗化處理基體表面。

圖1 冷噴涂預(yù)制粉末微觀形貌

表1 冷噴涂前設(shè)計的金屬粉末各元素質(zhì)量分數(shù)

Tab.1 the mass percentage of each element of metal powder designed before cold spraying wt.%

1.2 涂層的微觀組織及性能檢測

采用白俄羅斯國立技術(shù)大學(xué)設(shè)計制造的低壓冷噴涂設(shè)備（GDU-3-15）在45#鋼基體上預(yù)制混合金屬涂層，冷噴涂設(shè)備工藝參數(shù)見表2。對冷噴涂制備的混合金屬涂層進行感應(yīng)重熔處理，原位合成高熵合金涂層。感應(yīng)重熔加熱功率選用1.5～2.2 kW，加熱時間為10～15 s。

采用D/MAX2500PC型X射線衍射儀（XRD）對冷噴涂混合金屬涂層與原位合成高熵合金涂層表面進行相結(jié)構(gòu)分析，掃描速度為4 (°)/min，掃描步長為0.02°，加速電壓為40 kV，電流為40 mA，衍射角為20°～90°。采用QuantaFEG450場發(fā)射掃描電子顯微鏡（SEM）、能譜儀（EDS）對高熵合金涂層表面微觀形貌結(jié)構(gòu)和微區(qū)成分進行分析。使用HV1000型顯微硬度計測量試樣的硬度，選取維氏硬度，在試樣表面選取5個點測量，然后求其平均值。采用美國BRUKER公司生產(chǎn)的UMT-Tribolab型摩擦設(shè)備，以直徑為6 mm的氧化鋁小球作為對磨件，在室溫干滑動條件下測試合金涂層的摩擦學(xué)性能，試驗前需要將涂層和對磨件小球用酒精擦拭干凈，摩擦方式為往復(fù)式。摩擦試驗參數(shù)設(shè)置為：加載載荷7.5 N，摩擦行程3 mm，頻率3 Hz，摩擦?xí)r間20 min。涂層的磨損率可以用公式（1）計算[20]。

式中：為磨損率，mm3/(N·m)；為磨損的橫截面積；為磨損痕長度，mm；為累積摩擦功，N·m；為施加的載荷力，N；為滑動頻率，Hz；為摩擦?xí)r間，min。

表2 冷噴涂設(shè)備工藝參數(shù)

Tab.2 Process parameters of cold spraying equipment

2 結(jié)果與討論

2.1 冷噴涂CuNiCoFeCrAl2.3混合金屬涂層微觀組織及相組成

圖2是冷噴涂混合金屬涂層橫截面的微觀形貌和表面XRD圖譜。由圖2a可看出，冷噴涂涂層組織致密，孔隙小且分散，通過Image軟件測得涂層的孔隙率為0.45%±0.13%。從橫截面形貌圖中可以看出，基體與涂層之間以機械咬合的方式結(jié)合在一起，結(jié)合界面存在明顯的不平整。從圖2b可以看出，在冷噴過程中各個金屬粒子均未發(fā)生相變，涂層中的各種元素均以金屬單質(zhì)相的方式存在。圖3為圖2a對應(yīng)的EDS圖，各元素比較均勻地分布在涂層中，這為下一步感應(yīng)重熔原位合成CuNiCoFeCrAl2.3高熵合金涂層奠定了良好的基礎(chǔ)。

圖2 冷噴涂預(yù)制混合粉末涂層

圖3 冷噴涂涂層的EDS分析

2.2 冷噴涂輔助原位合成CuNiCoFeCrAl2.3高熵合金涂層的相結(jié)構(gòu)

圖4a是冷噴涂金屬混合涂層經(jīng)過感應(yīng)重熔原位合成CuNiCoFeCrAl2.3高熵合金涂層表面宏觀照片及XRD衍射圖譜。由圖4a可以看出，經(jīng)過感應(yīng)重熔表面光滑平整，沒有明顯的裂紋。說明本試驗采用感應(yīng)重熔工藝適合制備高熵合金涂層。由圖4b可以看出，涂層由單一BCC結(jié)構(gòu)固溶體組成。由布拉格方程2sin=可得BCC的晶格常數(shù)為0.372 1 nm，衍射峰的位置2大約為44°、65°和82°，與α-Fe的位置接近。根據(jù)圖4中的XRD分析，在CuNiCoFeCrAl2.3高熵合金涂層中沒有金屬間化合物出現(xiàn)。簡單固溶的高熵合金涂層可以根據(jù)以下參數(shù)確定[21-23]，即混合熵Δmix，混合熵參數(shù)，是元素原子尺寸的均方差。這些參數(shù)的表達式如下：

當高熵合金系統(tǒng)中滿足Δmix≥1.61、≥1.1、≤6.6，高熵合金易于形成穩(wěn)定的固溶體結(jié)構(gòu)。針對本研究中的高熵合金涂層系統(tǒng)分析這些參數(shù)，計算結(jié)果見表3。CuNiCoFeCrAl2.3多組元合金形成了穩(wěn)定的固溶體結(jié)構(gòu)，與XRD和微觀組織分析結(jié)果一致。根據(jù)高熵合金的概念和高熵合金固溶體形成條件，可以確定本文原位合成的涂層為簡單的BCC結(jié)構(gòu)的CuNiCoFeCrAl2.3高熵合金涂層。

2.3 冷噴涂輔助原位合成CuNiCoFeCrAl2.3高熵合金涂層的微觀組織

高熵合金涂層的優(yōu)異性能主要來自于高熵合金晶格畸變效應(yīng)。根據(jù)Hume-Rothery準則[24]可以通過CuNiCoFeCrAl2.3高熵合金中的原子尺寸差異計算出合金的晶格應(yīng)變，CuNiCoFeCrAl2.3高熵合金涂層的晶格應(yīng)變是4.13%。從晶體學(xué)角度講，BCC結(jié)構(gòu)相對較為松散，致密度僅為68%[25]，BCC相更容易發(fā)生變形以釋放晶格畸變能[26]。CuNiCoFeCrAl2.3高熵合金涂層的晶格應(yīng)變屬于較大的晶格變形。因此，該涂層傾向形成BCC結(jié)構(gòu)的組織，體現(xiàn)出更好的固溶強化效果。

圖5是冷噴涂輔助原位合成CuNiCoFeCrAl2.3高熵合金涂層的SEM圖。截面上涂層組織細密，涂層與基體間有較明顯的界面。由圖5b可知，涂層主要以樹枝晶的方式生長。在圖5b中有一些黑色斑點，這是因為冷噴涂CuNiCoFeCrAl2.3混合金屬涂層中存在少量的孔隙，在感應(yīng)重熔過程中，孔隙中的空氣會氧化涂層中的金屬元素，產(chǎn)生少量的Al2O3金屬氧化物。圖6是圖5b的面掃描分析結(jié)果，發(fā)現(xiàn)各元素較均勻地分布在涂層中。

圖4 感應(yīng)重熔CuNiCoFeCrAl2.3高熵合金涂層的宏觀照片及XRD圖譜

表3 CuNiCoFeCrAl2.3高熵合金固溶體形成標準條件參數(shù)值

Tab.3 Parameter values of standard conditions for the formation of CuNiCoFeCrAl2.3 high-entropy alloy solid solution

圖5 CuNiCoFeCrAl2.3高熵合金涂層的截面和表面形貌

圖6 圖5b中顯微組織SEM及相應(yīng)的EDS成分分析

將圖5b中的枝晶區(qū)域定義為區(qū)域，枝晶間區(qū)域定義為區(qū)域，然后EDS成分分析（分別見圖7a和圖7b）。枝晶內(nèi)區(qū)域主要富含Co、Cr、Fe和Ni，而枝晶間區(qū)域則富含Cu和Al。這是因為Cu與Fe、Cr、Co、Ni元素間的混合焓均為正（見表4），導(dǎo)致Cu元素與這些元素的結(jié)合能力、互溶性差，阻止了Cu元素進入枝晶區(qū)域；Cu與Al的混合焓低，并且易于結(jié)合。根據(jù)非平衡凝固理論，初次凝固區(qū)域（枝晶區(qū)域）富含高熔點元素（Fe、Co、Cr、Ni），而枝晶間區(qū)域（即最終的凝固區(qū)域）通常富含低熔點（Cu）元素。EDS成分分析發(fā)現(xiàn)，枝晶區(qū)域和晶間區(qū)域的Al濃度非常接近，這與Wu等[27-28]的研究結(jié)果一致，即Al原子比的增加有利于BCC相形成。

圖7 a、b區(qū)域 SEM形貌和相應(yīng)的面譜總圖

表4 元素間混合焓

Tab.4 Enthalpy of mixing between elements kJ/mol

2.4 冷噴涂輔助原位合成CuNiCoFeCrAl2.3高熵合金涂層的硬度和摩擦性能

圖8a是對冷噴涂輔助原位合成的CuNiCoFeCrAl2.3高熵合金涂層硬度及摩擦性能的檢測結(jié)果。其中圖8a的橫坐標是CuNiCoFeCrAl2.3高熵合金涂層表面隨機取5個點進行顯微硬度測試，涂層表面硬度均勻，不同測試點上的硬度數(shù)值波動較小，CuNiCoFeCrAl2.3高熵合金涂層的平均硬度為576HV左右。45#鋼基體的顯微硬度為170HV左右，CuNiCoFeCrAl2.3高熵合金涂層硬度高的原因是感應(yīng)重熔后涂層組織由簡單的BCC結(jié)構(gòu)固溶體組成。George等[29]研究認為，高熵合金的高硬度是固溶強化和晶界強化綜合作用的結(jié)果。固溶強化主要是由于合金元素原子半徑相差較大引起的晶格畸變，而晶界強化則是由于感應(yīng)重熔過程中的快速凝固，即快速凝固速率會抑制晶粒長大，導(dǎo)致晶界數(shù)目增加，從而導(dǎo)致高熵合金涂層的硬度增加。由文獻報道[30-31]可知，冷噴涂輔助感應(yīng)重熔CuNiCoFeCrAl2.3高熵合金涂層與鑄塊的CuNiCoFeCrAl2.3高熵合金涂層的硬度幾乎相同。圖8b是45#基體和CuNiCoFeCrAl2.3高熵合金涂層的摩擦曲線圖，基體45#鋼的摩擦因數(shù)為0.68，CuNiCoFeCrAl2.3高熵合金涂層的摩擦因數(shù)為0.38。

圖8 CuNiCoFeCrAl2.3高熵合金涂45#鋼基體發(fā)顯微硬度和摩擦因數(shù)

圖9是磨損表面的形貌。如圖9a所示，對45#鋼基體進行摩擦試驗后，表面有材料撕裂、剝落的痕跡，沒有明顯的磨料切割痕跡，由此可以推斷45#鋼基體的磨損主要是黏著磨損。這是因為45#鋼基體硬度低、塑性好，在摩擦過程中容易發(fā)生塑性變形。當磨損剪切點在基體材料內(nèi)部時，基體材料會發(fā)生撕裂和轉(zhuǎn)移。圖9b是CuNiCoFeCrAl2.3高熵合金涂層摩擦試驗后的表面形貌，在磨損表面上出現(xiàn)了犁溝和少量材料剝落痕跡，這說明CuNiCoFeCrAl2.3高熵合金涂層的磨損以磨粒磨損為主。材料的硬度越高，耐磨性越好[32]。表5是45#鋼基體和CuNiCoFeCrAl2.3高熵合金涂層的磨損率，45#鋼基體的磨損率為6.44× 10?5mm3/(N·m)，CuNiCoFeCrAl2.3高熵合金涂層的磨損率2.95×10?5mm3/(N·m)。

圖9 磨損表面的形貌

表5 是45#鋼基體和CuNiCoFeCrAl2.3高熵合金涂層的磨損率

Tab.5 shows the wear rate of 45# steel matrix and CuNiCoFeCrAl2.3 high entropy alloy coating

3 結(jié)論

1）冷噴涂輔助原位合成CuNiCoFeCrAl2.3高熵合金涂層主要由單一的BCC固溶相組成，其微觀結(jié)構(gòu)主要由樹枝晶組織，Cu在枝晶間區(qū)域富集，而Fe、Co、Cr、Ni分布在枝晶內(nèi)部，Al均勻分布在2個區(qū)域。

2）冷噴涂輔助原位合成CuNiCoFeCrAl2.3高熵合金涂層的顯微硬度為576HV左右，是45#鋼基底的3倍。

3）冷噴涂輔助原位合成CuNiCoFeCrAl2.3高熵合金涂層的平均摩擦因數(shù)為0.38，約為45#鋼基底的56%，在干滑動條件下，冷噴涂輔助原位合成CuNiCoFeCrAl2.3高熵合金涂層的磨損率為2.95×10?5mm3/(N·m)，比45#鋼基材低59%。

[1] YEH J W, CHEN S K, LIN S J, et al. Nanostructured High-Entropy Alloys with Multiple Principal Elements: Novel Alloy Design Concepts and Outcomes[J]. Adva-nced Engineering Materials, 2004, 6(5): 299-303.

[2] CANTOR B, CHANG I T H, KNIGHT P, et al. Micro-structural Development in Equiatomic Multicomponent Alloys[J]. Materials Science and Engineering: A, 2004, 375-377: 213-218.

[3] OTTO F, YANG Y, BEI H, et al. Relative Effects of Enthalpy and Entropy on the Phase Stability of Equiato-mic High-Entropy Alloys[J]. Acta Materialia, 2013, 61(7): 2628-2638.

[4] QIU Yao, THOMAS S, GIBSON M A, et al. Corrosion of High Entropy Alloys[J]. Npj Materials Degradation, 2017, 1: 15.

[5] 趙伊, 曹京宜, 方志剛, 等. 耐蝕高熵合金在島礁裝備中的應(yīng)用前景[J]. 裝備環(huán)境工程, 2021, 18(11): 42-50.

ZHAO Yi, CAO Jing-yi, FANG Zhi-gang, et al. Applica-tion Prospects of Corrosion-resistant High-entropy Alloys in Island and Reef Equipment[J]. Equipment Environ-mental Engineering, 2021, 18(11): 42-50.

[6] FU Zhi-qiang, JIANG Lin, WARDINI J L, et al. A High- Entropy Alloy with Hierarchical Nanoprecipitates and Ult-rahigh Strength[J]. Science Advances, 2018, 4(10): 8712.

[7] LIU Jing-da, GUAN Yu-xin, XIA Xue-chen, et al. Laser Cladding of Al0.5CoCrCuFeNiSi High Entropy Alloy Coa-ting without and with Yttria Addition on H13 Steel[J]. Crystals, 2020, 10(4): 320.

[8] 張玉林, 龐雅潔, 海潮, 等. 鈦合金表面微弧氧化涂層在模擬海洋環(huán)境下摩擦腐蝕規(guī)律研究[J]. 裝備環(huán)境工程, 2021, 18(6): 42-50.

ZHANG Yu-lin, PANG Ya-jie, HAI Chao, et al. Tribo- corrosion Behaviours of Microarc Oxidation Coating on Titanium Alloy Surface in Simulated Marine Environ-ment[J]. Equipment Environmental Engineering, 2021, 18(6): 42-50.

[9] ZENG Qun-feng, XU Ya-ting. A Comparative Study on the Tribocorrosion Behaviors of AlFeCrNiMo High Ent-ropy Alloy Coatings and 304 Stainless Steel[J]. Materials Today Communications, 2020, 24: 101261.

[10] LEHTONEN J, KOIVULUOTO H, GE Yan-ling, et al. Cold Gas Spraying of a High-Entropy CrFeNiMn Equia-tomic Alloy[J]. Coatings, 2020, 10(1): 53.

[11] YE Xiao-yang, MA Ming-xing, CAO Y, et al. The Pro-perty Research on High-Entropy Alloy AlFeCoNiCuCr Coating by Laser Cladding[J]. Physics Procedia, 2011, 12: 303-312.

[12] SOARE V, BURADA M, CONSTANTIN I, et al. Electro-chemical Deposition and Microstructural Characterization of AlCrFeMnNi and AlCrCuFeMnNi High Entropy Alloy Thin Films[J]. Applied Surface Science, 2015, 358: 533-539.

[13] HUANG P K, YEH J W, SHUN T T, et al. Multi-Prin-cipal-Element Alloys with Improved Oxidation and Wear Resistance for Thermal Spray Coating[J]. Advanced Engi-neering Materials, 2004, 6(12): 74-78.

[14] ANG A S M, BERNDT C C, SESSO M L, et al. Plasma- Sprayed High Entropy Alloys: Microstructure and Prope-rties of AlCoCrFeNi and MnCoCrFeNi[J]. Metallurgical and Materials Transactions A, 2015, 46(2): 791-800.

[15] YIN Shuo, LI Wen-ya, SONG Bo, et al. Deposition of FeCoNiCrMn High Entropy Alloy (HEA) Coating via Cold Spraying[J]. Journal of Materials Science & Techno-logy, 2019, 35(6): 1003-1007.

[16] ANUPAM A, KUMAR S, CHAVAN N M, et al. First Report on Cold-Sprayed AlCoCrFeNi High-Entropy Alloy and Its Isothermal Oxidation[J]. Journal of Materials Res-earch, 2019, 34(5): 796-806.

[17] HAN Chao, MA Li, SUI Xu-dong, et al. Influence of Low Energy Density Laser re-Melting on the Properties of Cold Sprayed FeCoCrMoBCY Amorphous Alloy Coa-tings[J]. Coatings, 2021, 11(6): 695.

[18] 馮力, 王貴平, 安國升, 等. 一種原位合成低壓冷噴涂CuNiCoFeCrAl(2.8)高熵合金涂層的制備方法[P]. CN110344047A, 2019-10-18.

FENG Li, WANG Gui-ping, AN Guo-sheng, et al. Prepa-ration Method of In situ Synthetic Low Pressure Cold Spraying CuNiCoFeCrAl(2.8) High Entropy Alloy Coa-ting[P]. CN110344047A, 2019-10-18.

[19] 馮力, 胡昱軒, 李文生, 等. 冷噴涂輔助原位合成CuFeCrAlNiTi高熵合金涂層的組織性能研究[J]. 表面技術(shù), 2021, 50(7): 194-202.

FENG Li, HU Yu-xuan, LI Wen-sheng, et al. Microstruc-ture and Properties of CuFeCrAlNiTi High Entropy Alloy Coating Prepared by Cold Spray Assisted In-Situ Synt-hesis[J]. Surface Technology, 2021, 50(7): 194-202.

[20] WANG Ying, LU Xiao-xing, YUAN Ning-yi, et al. A Novel Nickel-Copper Alternating-Deposition Coating with Excellent Tribological and Antibacterial Property[J]. Journal of Alloys and Compounds, 2020, 849: 156222.

[21] ZHANG Yong, ZUO Ting-ting, TANG Zhi, et al. Microst-ructures and Properties of High-Entropy Alloys[J]. Prog-ress in Materials Science, 2014, 61: 1-93.

[22] YANG X, ZHANG Y. Prediction of High-Entropy Stabi-lized Solid-Solution in Multi-Component Alloys[J]. Mate-rials Chemistry and Physics, 2012, 132(2-3): 233-238.

[23] GUO Sheng, HU Qiang, NG C, et al. More than Entropy in High-Entropy Alloys: Forming Solid Solutions or Amor-phous Phase[J]. Intermetallics, 2013, 41: 96-103.

[24] ZHOU Y J, ZHANG Y, WANG F J, et al. Phase Trans-formation Induced by Lattice Distortion in Multiprincipal Component CoCrFeNiCuAl1–xSolid-Solution Alloys[J]. Applied Physics Letters, 2008, 92(24): 241917.

[25] 余永寧. 金屬學(xué)原理[M]. 北京: 冶金工業(yè)出版社, 2000.

YU Yong-ning. Principle of Metal Science[M]. Beijing: Metallurgical Industry Press, 2000.

[26] GUO Lin, WU Wen-qian, NI Song, et al. Effects of Anne-aling on the Microstructural Evolution and Phase Transi-tion in an AlCrCuFeNi2High-Entropy Alloy[J]. Micron, 2017, 101: 69-77.

[27] CHUANG Ming-hao, TSAI M H, WANG W R, et al. Microstructure and Wear Behavior of AlCo1.5CrFeNi1.5TiHigh-Entropy Alloys[J]. Acta Materialia, 2011, 59(16): 6308-6317.

[28] [28] WU J M, LIN S J, YEH J W, et al. Adhesive Wear Behavior of AlCoCrCuFeNi High-Entropy Alloys as a Function of Aluminum Content[J]. Wear, 2006, 261(5-6): 513-519.

[29] GEORGE E P, RAABE D, RITCHIE R O. High-Entropy Alloys[J]. Nature Reviews Materials, 2019, 4(8): 515-534.

[30] JOSEPH J, HAGHDADI N, SHAMLAYE K, et al. The Sliding Wear Behaviour of CoCrFeMnNi and AlCoCrFeNi High Entropy Alloys at Elevated Temperatures[J]. Wear, 2019, 428-429: 32-44.

[31] TIAN Fu-yang, VARGA L K, CHEN Nan-xian, et al. Empirical Design of Single Phase High-Entropy Alloys with High Hardness[J]. Intermetallics, 2015, 58: 1-6.

[32] QIU Xing-wu. Microstructure, Hardness and Corrosion Resistance of Al2CoCrCuFeNiTiHigh-Entropy Alloy Coa-tings Prepared by Rapid Solidification[J]. Journal of Alloys and Compounds, 2018, 735: 359-364.

Microstructure and Properties of CuNiCoFeCrAl2.3High Entropy Alloy Coating Prepared by Cold Spray Assisted in Situ Synthesis

1,2,1,1,1,1,1,2

(1. College of Material Science and Technology, Lanzhou University of Technology, Lanzhou 730050, China; 2. State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals, Lanzhou University of Technology, Lanzhou 730050, China)

In recent years, the rapid development of material surface treatment technology plays a particularly important role in the progress of modern science and technology, industry and economic development. Surface treatment technology is an important method to improve and repair matrix materials. It can improve the strength, hardness, wear resistance and corrosion resistance of materials. Preparing a layer of alloy coating on the surface of ordinary industrial materials is one of the most effective measures of surface treatment. high entropy alloy coating assisted in situ synthesis by cold spraying was prepared，This method can effectively eliminate the interface between powder particles in cold spraying coating. Improve the adhesion and cohesion of the coating, The adhesion of the coating can reach 120 Mpa. In this method, the high entropy alloy powder is not required to be prefabricated, and the mixed metal powder is used as the spraying material to prepare the prefabricated mixed metal coating on the substrate. High entropy alloy coating was synthesized in situ by induction remelting technique. Therefore, this method has the advantages of low preparation cost, short cycle and easy to adjust the composition of the coating. High entropy alloys have high entropy effect in thermodynamics, lattice distortion effect in structure, hysteresis diffusion effect in dynamics, "cocktail" effect in performance and stability in structure. These effects give the alloys excellent mechanical properties such as high strength, good corrosion resistance and excellent wear resistance. These new metal materials are suitable for many engineering applications, Scholars prepared high entropy alloy as surface coating for wear and corrosion conditions, which can not only improve the service life and performance of metal parts, but also reduce the cost of preparation. In order to improve the surface corrosion and wear resistance of ordinary metal materials, a technology for preparing CuNiCoFeCrAl2.3high entropy alloy coating with good performance on the surface of common metal materials was proposed. Methods The mixed metal coating was prepared on 45#steel by cold spraying at low pressure, and then synthesized into CuNiCoFeCrAl2.3high entropy alloy coating by induction remelting technology. The phase composition, microstructure, hardness and wear resistance of the coating were analyzed by scanning electron microscope (SEM), X-ray diffraction (XRD)、energy dispersive spectrometer (EDS)、microhardness tester and abrasive wear tester. Results The microstructure of CuNiCoFeCrAl2.3high entropy alloy coating was compact, the elements were uniformly distributed, the alloy coating was composed of simple BCC phase, and the microstructure of the coating showed typical dendrite structure. Co、Cr、Fe and Ni are mainly abundant in the inner dendrite region, while Cu and Al are abundant in the inter-dendrite region. The microhardness of CuNiCoFeCrAl2.3high entropy alloy coating is three times that of 45#steel alloy matrix under dry friction condition. The wear rate of CuNiCoFeCrAl2.3high entropy alloy coating under dry sliding condition is 59% lower than that of 45#steel substrate, and the friction coefficient is 0.38. the wear rate of CuNiCoFeCrAl2.3high entropy alloy coating is 2.95×10?5mm3/(N·m). The CuNiCoFeCrAl2.3high entropy alloy coating assisted by cold spraying has high hardness and excellent wear resistance.

high entropy alloy; cold spray; induction remelting; microstructure; wear resistance

TG174.442

A

1001-3660(2022)10-0344-09

10.16490/j.cnki.issn.1001-3660.2022.10.037

2021–08–17；

2021–11–29

2021-08-17；

2021-11-29

國家重點研發(fā)計劃（2016YFE0111400）；國家自然科學(xué)基金（52075234）；中國博士后科學(xué)基金項目（2018-63-200618-34）；甘肅省青年博士基金項目（2021QB-043）

National Key R&D Plan (2016YFE0111400); National Natural Science Foundation of China (52075234); China Postdoctoral Science Foundation Program (2018-63-200618-34); Gansu Young Doctor Fund Project (2021QB-043)

馮力（1981—），男，博士，教授，主要研究方向為冷噴涂增材制造技術(shù)、金屬陶瓷復(fù)合涂層的制備與研究。

FENG Li (1981-), Male, Doctor, Professor, Research focus: manufacturing technology of cold spraying additive, preparation and research of metal ceramic composite coating.

馮力, 馬凱, 楊偉杰, 等. 冷噴涂輔助原位合成CuNiCoFeCrAl2.3高熵合金涂層組織與性能研究[J]. 表面技術(shù), 2022, 51(10): 344-352.

FENG Li, MA Kai, YANG Wei-jie, et al. Microstructure and Properties of CuNiCoFeCrAl2.3High Entropy Alloy Coating Prepared by Cold Spray Assisted in Situ Synthesis[J]. Surface Technology, 2022, 51(10): 344-352.

責(zé)任編輯：萬長清