单向凝固制备亚共晶成分InSb-NiSd共晶复合材料

Unidirectionally Solidified Hypo-eutectic InSb-NiSb Composites

利用单向凝固技术制备共晶复合材料的工序比制造玻璃纤维或碳纤维增强的复合材料简单。它一般只需要通过单向凝固,而凝固条件符合F.R.Mollard和M.C.Flemings提出的判别式:就可以。 本文用Bridgman垂直单向凝固法对两种亚共晶成分(1.45和1.63wt％Nisb)的InSb-NiSb合金分别在温度梯度G=80℃/cm,并用6种凝固速度(R=0.05,0.08,0.10,0.20,0.50和1.00mm/min)制取了φ11mm×90mm左右的锭棒。 经金相检验锭棒纵截面的组织分布,结果表明从底部0.11至(0.8～0.9)1处,基本上都获得了规则排列的InSb-NiSb共晶组织——共晶复合材料。这说明所用的(G/R)值皆大于或等于(CE-C_0)/D值。 经测定试样在0.51处横截面的NiSb纤维间距(λ)和凝固速度(R)的关系如下: 1.45wt％NiSb合金:λ~2R=2.04×10^(-10)cm3/sec,(G(?)80℃/cm); 1.63wt％NiSb合金:λ~2R=1.56×10^(-10)cm3/sec,(G(?)65℃/cm);含NiSb较少的共晶,其λ2R值较大。亚共晶成分比共晶成分(1.8w/oNiSb)的λ2R=0.76×10^(-10)cm3/sec(G+125+5℃/cm)大。 以上试样在室温,磁感应强度B=1T下的电阻(R_B)与零磁场中的电阻(R_0)的比值 (R_B)/(R_0)=9.2～12.9(1.45wt％NiSb合金); (R_B)/(R_0)=9.6～13.2(1.63wt％NiSb合金);虽然它们比共晶成分(在相同的凝固速度下)

InSb-NiSb hypo-eutectics of 1.45 and 1.63wt% NiSb, unidirectionally solidified with Bridgman method under temperature gradients G = 80 and 65℃cm respectively and six solidification rates (R = 0.05, 0.08, 0.1 0.2, 0.5 and 1.0 mm/min ) are studied.1. Eutectic composite structures are found in ingot regions from about0.11 to (0.8-0.9)1. It shows that the values of R/G used are in accord withMollard-Flemings criterion R/G≥DL/m(CE-C0)2. Relations between fibre spacing (λ) and solidification rate (R) are found as followswhich are greater than that of eutectic composition (1.8wt% NiSb, G = 125 ℃/cm) λ2R = 0.76×the greater the values of λ2R3. At room temperature the ratio of resistance with magnetic inductance B=10 kGs, Rs to resistance with zero magnetic inductance RO:RO/RB=9.2-12.9(1.45wt% NiSb),RO/RB=12-15.which are smaller than that of eutectic composition RO/RB = 12-15