How to add username in welcome email after registration?

I've been searching everywhere for a solution to my issue. I've created a welcome email, created the Mailable, Controller, and View. But for some reason, the $user isn't showing in the email itself. It's blank. Am I missing something?

Mailable

<?php

namespace App\Http\Mail;

use App\User;
use Illuminate\Bus\Queueable;
use Illuminate\Mail\Mailable;
use Illuminate\Queue\SerializesModels;
use Illuminate\Contracts\Queue\ShouldQueue;


class Welcome extends Mailable
{
    use Queueable, SerializesModels;

    public $user; 
    /**
    * @return void
    */
    public function _construct(User $user)
    {
        $this->user = $user;
    }

    /**
    *@return $this
    */
    public function build()
    {
        return $this->view('emails.welcome')->subject('Welcome to');
    }
}

Controller

<?php

namespace App\Http\Controllers\Auth;

use Mail;
use App\User;
use App\Http\Controllers\Controller;
use Illuminate\Support\Facades\Validator;
use Illuminate\Foundation\Auth\RegistersUsers;
use Illuminate\Support\Facades\Auth;
use App\Http\Mail\Welcome;



class RegisterController extends Controller
{
    /*
    |--------------------------------------------------------------------------
    | Register Controller
    |--------------------------------------------------------------------------
    |
    | This controller handles the registration of new users as well as their
    | validation and creation. By default this controller uses a trait to
    | provide this functionality without requiring any additional code.
    |
    */

    use RegistersUsers;

    /**
     * Where to redirect users after registration.
     *
     * @var string
     */
    protected $redirectTo = '/dashboard';

    /**
     * Create a new controller instance.
     *
     * @return void
     */
    public function __construct()
    {
        $this->middleware('guest');
    }

    /**
     * Get a validator for an incoming registration request.
     *
     * @param  array  $data
     * @return \Illuminate\Contracts\Validation\Validator
     */
    protected function validator(array $data)
    {
        return Validator::make($data, [
            'first_name' => 'required|max:255',
            'last_name' => 'required|max:255',
            'email' => 'required|email|max:255|unique:users',
            'mobile' => 'required',
            'password' => 'required|min:6|confirmed',
        ]);
    }

    /**
     * Create a new user instance after a valid registration.
     *
     * @param  array  $data
     * @return User
     */
    protected function create(array $data)
    {
        $user = User::create([
                            'first_name' => $data['first_name'],
                            'last_name' => $data['last_name'],
                            'email' => $data['email'],
                            'mobile' => $data['mobile'],
                            'password' => bcrypt($data['password']),
                            'payment_mode' => 'CASH',
                            ]);



        Mail::to($data['email'])->send(new Welcome($user));

        return $user;
        // send welcome email here
    }


    /**
     * Show the application registration form.
     *
     * @return \Illuminate\Http\Response
     */

    public function showRegistrationForm()
    {

        return view('user.auth.register');
    }

}

View (shortened to show problem)

Welcome 

As was mentioned, everything passes successfully, however, in the email itself, the name of the user is blank. Please help!

via Chebli Mohamed