Excellent isotropic mechanical properties of directed energy deposited Mg-Gd-Y-Zr alloys via establishing homogeneous equiaxed grains embedded with dispersed nano-precipitation

Additive manufacturing of magnesium and its alloys: process-formability-microstructure-performance relationship and underlying mechanism

“…(3) Furthermore, some investigations reported that the vertical sample demonstrated comparable mechanical properties to the horizontal sample [78,90,122,127,145,148]. The difference between the mechanical properties in two directions was within the range of error.…”

“…For instance, Chang et al utilized k H = 164 MPa•µm 1/2 to evaluate the grain boundary strengthening effect and indicated that the contribution of grain boundary strengthening in LPBF-processed Mg-9Al-1Zn-0.5Mn alloy could reach 38.1% of the overall yield strength [150], which is smaller than the results shown by Deng et al If the utilized k H value was increased to 280 MPa•µm 1/2 (which is the same as the k H value used by Deng et al), the contribution proportion of grain boundary strengthening would be increased to 65.2%, which is consistent with the investigation by Deng et al The similar comparison is also found in the WAAM-processed Mg alloys. Li et al [151] and Cao et al [148] used k H = 158 MPa•µm 1/2 and 250 MPa•µm 1/2 , respectively, to evaluate the grain boundary strengthening effects in the WAAM-processed Mg alloys. Li et al found that the contribution of grain boundary strengthening to yield strength in the WAAM-processed AZ31 alloy only occupied ∼20% of the overall yield strength, while Cao et al indicated that the proportion of grain boundary strengthening effect could reach 36.4% in the WAAM-processed Mg-Gd-Y-Zr alloy.…”

Revealing precipitation behavior and mechanical response of wire-arc directed energy deposited Mg-Gd-Y-Zr alloy by tailoring aging procedures

“…However, the strength of those works is limited to less than 300 MPa due to their nonheat treatability, making it difficult for practical engineering applications [20,22]. With the steady improvement of wire preparation technology in recent years, some researchers have shifted their focus to the Mg-RE alloys [6,7,9,26,27]. Specifically, Tong et al [26] revealed the effect of thermal profiles inherent in the quasi-wire-arc DED of WE43 alloy on the inhomogeneous microstructure and mechanical properties.…”

“…Specifically, Tong et al [26] revealed the effect of thermal profiles inherent in the quasi-wire-arc DED of WE43 alloy on the inhomogeneous microstructure and mechanical properties. Cao et al [7] and Ma et al [9] successfully prepared high-quality GW63K alloy components using ultrasonic frequency pulsed and cold metal transfer (CMT) based wirearc DED, respectively. Meanwhile, dispersed nanoprecipitates were obtained by heat treatment, thereby substantially increasing the strength to about 350 MPa [7,9].…”

“…Cao et al [7] and Ma et al [9] successfully prepared high-quality GW63K alloy components using ultrasonic frequency pulsed and cold metal transfer (CMT) based wirearc DED, respectively. Meanwhile, dispersed nanoprecipitates were obtained by heat treatment, thereby substantially increasing the strength to about 350 MPa [7,9]. The effect of heat treatment on the phase transformation behavior and mechanical properties of wire-arc DED-prepared GWZ1031K alloy was also investigated by Cao et al [6].…”