(沈陽(yáng)工業(yè)大學(xué) 材料科學(xué)與工程學(xué)院，沈陽(yáng) 110870)
摘 要: 利用銅模鑄造制備直徑為1~4 mm的Mg72−xZn28Cax(x=1~6) 合金，采用XRD、DSC、SEM和力學(xué)性能試驗(yàn)機(jī)分別對(duì)合金的非晶形成能力、相組成、斷口形貌和力學(xué)性能進(jìn)行研究。結(jié)果表明：在x為3、4和5時(shí)，Mg72−xZn28Cax合金的非晶形成能力(以直徑表示)分別為2、3和2 mm；而當(dāng)x為1、2和6時(shí)，Mg72−xZn28Cax合金的非晶形成能力低于直徑為2 mm的；當(dāng)x為3和5時(shí)，直徑為2 mm的非晶態(tài)合金的屈服強(qiáng)度分別為591 MPa和662 MPa，塑性變形量分別為0.5%和0.2%；直徑為3、2和1 mm的Mg68Zn28Ca4非晶合金的屈服強(qiáng)度分別為540、611和610 MPa，塑性變形量分別為0.48%、1.28%和6.2%，Mg68Zn28Ca4非晶合金是目前所報(bào)道的塑性變形量最大的鎂基非晶合金；單位剪切面上彈性能的減少及其分布均勻性的改善是樣品尺寸減小促使塑性應(yīng)變量提高的主要原因。
關(guān)鍵字: Mg-Zn-Ca合金；非晶形成能力；塑性應(yīng)變；尺寸效應(yīng)
Mg-Zn-Ca alloys
（School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110870, China）
Abstract:The as-cast Mg72−xZn28Cax (x=1−6) alloys with diameter size of 1−4 mm were fabricated by using copper mold casting method. The glass forming ability (GFA), phases constituent, fracture surfaces and mechanical properties were investigated by X-ray diffractometry (XRD), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The results show that the GFA for alloys with x of 3, 4 and 5 are 2, 3 and 2 mm in diameter, respectively. While the GFA for alloys with x of 1, 2 and 6 is lower than that of alloy with 2 mm in diameter. The yield strength and plastic strain are 591 MPa and 0.5% for alloy with x of 3, 662 MPa and 0.2% for alloy with x of 5. Furthermore, the yield strength and plastic strain for Mg68Zn28Ca4 bulk metallic glass with diameters of 3, 2 and 1mm are 540 MPa and 0.48%, 611 MPa and 1.28%, 610 MPa and 6.2%, respectively. The Mg68Zn28Ca4 amorphous alloy shows the highest plastic strain in Mg-based bulk metallic glasses that have ever reported. The enhanced plastic strains with the reduction of sample size were suggested to come from the elastic energy reduction in a unit area on the shear plane as well as its homogeneous distribution in the sample.
Key words: Mg-Zn-Ca alloy; glass-forming ability; plastic strain; size effect
