(西安工業(yè)大學(xué) 材料與化工學(xué)院，西安 710021)
摘 要: 對(duì)經(jīng)過T6處理的兩種鑄造Al-Si合金(Si含量為12%和18%，質(zhì)量分?jǐn)?shù))進(jìn)行不同溫度(250、350、450、550 ℃)、時(shí)間2 h的熱暴露試驗(yàn)。采用表面粗糙度儀、金相顯微鏡、掃描電子顯微鏡、專業(yè)型同步熱分析儀等測(cè)試方法相互結(jié)合，對(duì)兩種Al-Si合金在高溫?zé)岜┞稐l件下表面狀態(tài)的變化進(jìn)行研究。結(jié)果表明：Al-x%Si二元合金的粗糙度變化基本遵循Ra, T6＞Ra, thermal exposure＞Ra, as-cast的規(guī)律；隨著熱暴露溫度的升 高，Al-12%Si粗糙度呈現(xiàn)先降低后升高的趨勢(shì)，Al-18%Si粗糙度呈現(xiàn)不斷升高的趨勢(shì)；合金表面粗糙度的變化與熱暴露試驗(yàn)過程中的Al/Si相界開裂和稀土相的析出有關(guān)；對(duì)比粗糙度及表面微觀形貌變化發(fā)現(xiàn)：Al-18%Si比Al-12%Si具有更加優(yōu)良的高溫穩(wěn)定性，即在較低溫度下，隨著Si含量的增加，Al-x%Si合金發(fā)生開裂的趨勢(shì)逐漸降低。
關(guān)鍵字: Al-Si合金；粗糙度；微觀組織；熱暴露
（School of Materials and Chemical Engineering, Xi’an Technological University, Xi’an 710021, China）
Abstract:Thermal exposure tests were performed on two cast Al-Si alloys by T6 heat treatment at different temperatures (250, 350, 450 and 550 ℃) for 2 h. The surface roughness tester, metallographic microscope, scanning electron microscope, simultaneous thermal analyzer and other testing methods were used to study the change of the surface state of two Al-Si alloys under high temperature thermal exposure conditions. The results show that the roughness change of Al-x%Si binary alloy basically follows the law of Ra, T6＞Ra, thermal exposure＞ Ra, as-cast; with the increase of thermal exposure temperature, the roughness of Al-12%Si tends to decrease first and then increases, while that of Al-18%Si tends to increase continuously. The change of alloy surface roughness is related to Al/Si phase boundary cracking and precipitation of rare earth phase during thermal exposure test. By comparing the roughness and phase changes, it is found that Al-18%Si has better high temperature stability than Al-12%Si. That is to say, at lower temperature, with the increase of Si content, the tendency of Al-x%Si cracking gradually decreases.
Key words: Al-Si alloys; roughness; microstructure; thermal exposure
