Actually, there are a lot of things that can go wrong in your code and i don't see any explicit error here. In pixel shader try
return float4(1.0f, 1.0f, 1.0f, 1.0f);
If you see your object white, probably problem lies in binding texture resource (DefaultTexture in your shader code). If still nothing appears, check that you update constant buffers with matrices correctly for the vertex shader and bind right render target for your pixel shader. Or maybe you placed vertices in the wrong order and rasterizer culls your geometry, try D3D11_CULL_NONE.