【摘要】：采用金相光學(xué)顯微鏡(OM),掃描電鏡(SEM),能譜儀(EDS)以及X射線衍射(XRD)等手段,研究了不同Gd含量(1%,2%,3%,原子分數(shù))與不同熱處理狀態(tài)(鑄態(tài),固溶態(tài),時效態(tài))對Mg-Gd-Zr合金顯微組織和力學(xué)性能的影響。結(jié)果表明:鑄態(tài)組織中,Gd元素富集在晶界,隨Gd含量增加,共晶組織增多,并逐漸呈網(wǎng)狀分布,合金的晶粒逐漸變小。經(jīng)過535℃,24 h固溶處理,共晶組織分解,殘留相主要為富Gd的方塊相,數(shù)量隨Gd含量升高增加,晶粒尺寸比鑄態(tài)組織長大。再經(jīng)過220℃,24 h時效處理,合金中析出第二相,晶粒尺寸與固溶態(tài)差別不大。合金的抗拉強度,屈服強度和硬度(R_m,R_(p0.2),HB)隨Gd含量增加呈上升趨勢,斷后伸長率隨Gd含量升高呈降低趨勢。經(jīng)過535℃,24 h固溶處理,消除了鑄造應(yīng)力,且使合金晶粒長大,降低了合金強度。時效處理后,合金中析出第二相,合金強度升高,且Gd含量越高析出第二相越多,強化效果越明顯。拉伸斷裂后,鑄態(tài)合金呈解理斷裂,固溶態(tài)合金呈穿晶斷裂,時效態(tài)合金呈沿晶斷裂。
[Abstract]:By means of optical microscope (OM), scanning electron microscope (OM), (SEM), energy spectrometer (EDS) and X-ray diffraction (XRD), the different contents of Gd (1 / 2 / 3, atomic fraction) and different heat treatment states (as cast) were studied. The effect of solution state and aging state on the microstructure and mechanical properties of Mg-Gd-Zr alloy. The results show that the Gd element is enriched at the grain boundary in the as-cast structure. With the increase of Gd content, the eutectic structure increases and gradually distributes as a network, and the grain size of the alloy becomes smaller. After solution treatment at 535 鈩，

本文編號：2378943